I think a mel procedure would probably be your best bet if your textures are applied to sprites with a "rand" function, or some other random value.
This question might be better answered by our new Melscript moderator, dannygan
Give him a try with your question, and see if he can come up with any good ideas...
Good luck!
Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
izzylong.com