Feature Request: Individual layering for multitimbral instruments

This seems like something that should have been implemented by now, but I've never found a way to do it...

If i have a multitimbral instrument, say Omnisphere, with multiple sounds on different channels and I want to map them across 2 keyboards in different ranges, I should be able to specify a separate range for each channel in MainStage. I know you can use stack mode in Omni to do this within a single range on one keyboard, but there are myriad circumstances in which this has not been possible, especially with less flexible plugs, like Kontakt. It also hamstrings the "Paste as alias" functionality unless you want the same range across every song.

PLEASE address this in a future update!

Love MainStage, has definitely made my live setup work better, but this would really change the game.

My $.02.