here's a mock-up:


if it's difficult to implement, we could start with making an optional separate column in UI for folded racks, so that they're always available when needed again, and perhaps adding solo and mute buttons would also help, since folded racks usually don't take too much space.
Then there's a tedious process of hiding and revealing several relevant racks. It could be solved along with simplifying simple routing routine (no pun untended
