Incremental leveled lists across different esps?

[ArcaneSmith]

So I'm making this mod and I want to make it modular for future updates, so people choose the item packs they want. But each module would have those books dropping from the same creatures, and initially i though that a leveled item list would add their items to another with the same id in another esp, but they replace each other. A dirty solution would be to use a different sublist that ends up in the same creature, but i believe it would create even more incompatibilities with other mods, overriding their item lists, plus eventually I'd run out of item sublists for said creature with like, three different modules.

 

So, in short, what I want is to have many esps adding items to the same creature instead of replacing them by whatever esp is last. So, is there a clean way to do this? Like, making leveled item lists incremental and not override each other? Or is there some other way to make a shared loot system between many esps where items add up but don't override each other? I've tried having the leveled list on an esm and have all esps linked to the esm, but it seems to make no difference. Please help this noobie! =D

 

Thanks!