Magento Select Categories inseide a categorie

Question

I have severall products that belong to multiple categories. What i need is some kind of layered navigation like this I have this kind of category tree:

• CAT A
• *Cat a1
• *Cat a2
• CAT B
• *Cat b1
• *Cat b2

CAT A its Brands, and CAT B is type of product.

In catalog when i go to Cat b1, i want to add a filter so it shows all the brands of the products. So the filter as Cat a1 and Cat a2, and if i filter Cat a1 it will only show products from Cat b1 that belong to Cat a1.

What i mean, is a intersection of both categories, and it will allways display like in layered navigation. Every time i enter a category, it must display the categories that the products inside of it also belongs to.

design/frontend///catalog/layer/view.phtml

    <?php if($this->canShowBlock()): ?>
<div class="block block-layered-nav">
    <div class="block-title">
        <strong><span><?php echo $this->__('Shop By') ?></span></strong>
    </div>
    <div class="block-content">
        <?php echo $this->getStateHtml() ?>
        <?php if($this->canShowOptions()): ?>
            <dl id="narrow-by-list">

                <?php $_filters = $this->getFilters() ?>
                <?php $counter=1; foreach ($_filters as $_filter): ?>

                <?php if($_filter->getItemsCount()): ?>
                <span>
                    <dt id="filter_heading"><?php echo $this->__($_filter->getName()) ?><span class="toggleBtn highlight" id="toggleBtn<?php echo $counter; ?>"></span></dt>
                    <dd id="filter_content<?php echo $counter; ?>" style="display:block;"><?php echo $_filter->getHtml() ?></dd>
                      <script type="text/javascript">
                        jQuery('#toggleBtn<?php echo $counter; ?>').click(function() {
                          jQuery('#filter_content<?php echo $counter; ?>').slideToggle('slow');
                           jQuery(this).toggleClass("highlight");
                        });
                    </script>
                    </span>
                <?php endif; $counter++; ?>
                <?php endforeach; ?>

            </dl>
            <script type="text/javascript">decorateDataList('narrow-by-list')</script>
        <?php endif; ?>
    </div>
</div>
<?php endif; ?>

Theme catalog.xml

<catalog_category_layered translate="label">
        <label>Catalog Category (Anchor)</label>
        <reference name="root">
            <action method="setTemplate"><template>page/2columns-left.phtml</template></action>
        </reference>
        <reference name="left">
            <block type="catalog/layer_view" name="catalog.leftnav" after="catalog.magicat" template="catalog/layer/view.phtml"/>
        </reference>
        <reference name="content">
            <block type="catalog/category_view" name="category.products" template="catalog/category/view.phtml">
                <block type="catalog/product_list" name="product_list" template="catalog/product/list.phtml">
                    <!-- <action method="addReviewSummaryTemplate"><type>default</type><template>review/helper/su.phtml</template></action> -->
                    <block type="catalog/product_list_toolbar" name="product_list_toolbar" template="catalog/product/list/toolbar.phtml">
                        <block type="page/html_pager" name="product_list_toolbar_pager"/>
                        <!-- The following code shows how to set your own pager increments -->
                        <!-- 
                            <action method="setDefaultListPerPage"><limit>10</limit></action>
                            <action method="setDefaultGridPerPage"><limit>8</limit></action>
                            <action method="addPagerLimit"><mode>list</mode><limit>10</limit></action>
                            <action method="addPagerLimit"><mode>list</mode><limit>20</limit></action>
                            <action method="addPagerLimit"><mode>list</mode><limit>30</limit></action>
                            <action method="addPagerLimit" translate="label"><mode>list</mode><limit>all</limit><label>All</label></action>
                            <action method="addPagerLimit"><mode>grid</mode><limit>8</limit></action>
                            <action method="addPagerLimit"><mode>grid</mode><limit>16</limit></action>
                            <action method="addPagerLimit"><mode>grid</mode><limit>24</limit></action>
                            <action method="addPagerLimit" translate="label"><mode>grid</mode><limit>all</limit><label>All</label></action>
                        -->
                    </block>
                    <!--action method="addColumnCountLayoutDepend"><layout>empty</layout><count>6</count></action>
                    <action method="addColumnCountLayoutDepend"><layout>one_column</layout><count>5</count></action>
                    <action method="addColumnCountLayoutDepend"><layout>two_columns_left</layout><count>4</count></action>
                    <action method="addColumnCountLayoutDepend"><layout>two_columns_right</layout><count>4</count></action>
                    <action method="addColumnCountLayoutDepend"><layout>three_columns</layout><count>3</count></action-->
                    <action method="setColumnCount"><count>3</count></action>
                    <action method="setToolbarBlockName"><name>product_list_toolbar</name></action>
                </block>
            </block>
        </reference>
    </catalog_category_layered>

Any help appreciatted.