Hey Sean,
I think I have a solution to your problem. The AE’s may not like it. Recently dealt with it on one of my shows.
Basically your problem lies in the sub-clipping of the multigroup. Once you subclip out from the multi, the resulting subclip loses all connection with the multigroup. It’s only source reference is it’s original group.
The solution is not to subclip but to actually CUT the portions of the multigroup you need to separate into a SEQUENCE. If you do this and use the resulting sequence the same way as the sub-groups (loading them in the source monitor and cutting from them) you will not lose matchback ability in your final cut.
Make sense? Let me know if I’m unclear.
Cheers,
Flynn