External xml file for joomla! template parameters

Question

I have the below code in templateDetails.xml file, in a sample custom Joomla! 2.5.x template.

<config>
    <fields name="params">
        <fieldset name="advanced" addfieldpath="/plugins/system/framework/elements">
            <field name="elements" type="elements" label="" addfieldpath="/plugins/system/framework/elements" />
        </fieldset>
    </fields>
</config>

I want to have an external .xml file with options like below?

<?xml version="1.0" encoding="utf-8"?><form name="template-options">
<fieldset name="toolbar-panel" label="TOOLBAR">
    <field name="presets" type="preset" mode="scroller" default="preset1" setbyurl="true" setinoverride="false" panel_position="left" show_label="false"/>
</fieldset>

I dont'want to add the fieldset inside templateDetails.xml, I want it external.

Is that possible?

Thank you.