How about building a function that creates a mask. Like lets say you have a picture or more and you want them to show on one part of the screen, than you can make another black shape on witch part you want them to show and make it a mask for the other images so they only appear where the shape is.
This could be made using set sub rect when there is only one image, but it gets a lot more complicated if you have animations that change the sub rect... lots of them+text+drawables... and I have no ideea how to do this if you want them to appear on any shape.
