How to render nested viewContainerRefs in Angular 8

Question

I have the following pattern in my .html file:

    <ng-container #1><.ng-container>
    <ng-template #12></ng-template>
    <ng-template #13></ng-template>
    <ng-container #2><.ng-container>
    <ng-template #21></ng-template>
    <ng-template #22></ng-template>
    </ng-template>

So basically there is container #2 in the template of container #1. How do I define these containerRefs and templateRefs so that they are connected and rendered in the component.ts file

I feel there is some connection missing in component file and that is why I am getting undefined for the nested container #2.

Please advice. Thanks.