Is it possible to have a dynamic groups position be based on a parent frame? What I would like to do is have my dynamic group appear at the bottom of my raid frames, vuhdo, and move based on the raid size, whether there are 2 rows or 5
You'd have to write some custom lua, but you can access all of the regions inside the WeakAuras.regions global and reposition them by setting frame coordinates or playing with it's anchor settings. There's no built in method of accomplishing it so it's not an easy task.
A quick and dirty method: duplicate the group, reposition it, then modify the load conditions so that they only activate on certain group sizes.