would it be possible to flip channel faders to show sends to a group when selecting a group mix, as it is when selecting an aux mix?
As already said groups are just an on / off channel by channel selection of a channel or channels to send to a group. That input to a group follows everything post fade from the selected channel.
An easy way to tell what channels are assigned to groups or mixes is to select the group or mix you want to work with and then to the left of the row of select buttons hit the “assign” button, that will light all the select buttons on the channels that are assigned to the mix or group that you have selected.
Also while holding the “assign” button yoy can hit the select buttons on each channel to select or de-select that channel from the selected mix or group.
