OK, I understand the principle but still do not know how to "apply" it.
Checking the box you indicate makes the subgroups apear, as shown by you...
But how do I define the subgroups? Am I limited since I only have presently one audio output (A1)? (line6 UX1 hooked on loud-speakers)
Hope you bring a lot of patience (son, who is that girl?) with you!!
Bernard