Send ahead option for assemblies?

I'm on 9.05.702.  I typically have 3-4 levels of subassemblies on jobs.  Jobs are processed in cells, so that once an asm 3 part is complete, it moves on in the cell and we start producing asm 2.  Once the first asm 2 piece is done, it moves on to start asm 1, and so on.  I like the send ahead feature, but I can only get it work on operations within the same assembly level.  Is there a way to schedule assemblies at the same time, with only a slight offset?