Element Template with More than One Active Cell

I'm creating some 3D signage for our Point Feature Defintions/Symbologies. In creating the Element Templates for the 3D portion of the Feature Symbology I would like the Element Template to be able to point to more than one Active Cell.

For example. I do not want to have to make a separate cell for a Stop Sign and then a second cell for a Stop Sign All-Way. I would like to be able to make a cell for the post, a cell for the stop sign, and then a cell for the all-way sign, and then combine all those in different manners for different element templates.

Is there a way to do this?

Thanks,
Chris