Workaround, yes... Ian, stay determined please smile
This is a wishlist. Wish hard! We need Santa awake and busy for Christmas... or maybe another Christmas..or the next...

If this ever comes to BIAB, the rules for selection should include: "inverse selection".
So my imagination gets me this workflow:

1)Select the bars you want to work with.
2)Inverse selection (this will reverse selected/unselected "selection". Meaning it will select everything but the bars you selected to work with)
3)Freeze selection

Only "unfrozen" bars that you selected initially will remain fluid for changes/regeneration....in theory. And again in theory, it should take MUCH less time.