I need to read up on how to do this
Simple. You need to have the current firmware for the feature. Hit rec/pause and enter the
channel trim display the same as you do now to adjust channel input levels one by one. Ordinarily you'd push the channel selection buttons one at a time to highlight and adjust the virtual control knob on the display one after the other until they are all adjusted correctly. To 'gang' any number of channels simply hold down the selection button for the first channel of the group you want to create, then before releasing it, push the selection button for the last channel of the group. When you do that, those two channels and any channels in-between them are ganged, and all of them are highlighted on the display and will be adjusted with a single knob turn. Pushing the selection button for any channel in the group then selects the entire group. Ungroup by doing the press and hold thing again for the first and last channels at each end of the group. At that point you can adjust channels individually or gang a different group of channels.
You can have more than one group at a time as long as the selections don't overlap, in other words, no channel can be included in more than one group. So you can make 3 separate stereo groups to have each adjustable as a pair, one big 6 channel group, or any combination of sequential channels you’d like.
You can have different gains within a group, simply by adjusting them before ganging. Once ganged those differences within the group are locked in and maintained, and the overall available adjustment range for the entire group becomes limited to the remaining range of the highest and lowest gains in the group.
In my example above, I'd first check to make sure the gains were equal on each of my mic channels 1-4, then group them and adjust them all simultaneously to my liking. Then I balanced the SBD inputs on channels 5-6 individually, then grouped them for a single stereo adjustment of SBD feed level. Once I had both the mics and SBD levels balanced well, I unganged those groups and made one big 6 channel group of all my inputs allowing me to quickly adjust everything at once. That way if an act like The Traveling McCoury's+LeeBoys followed Roy Bookbinder, I could quickly lower the gain across all 6 channels with one control knob without upsetting the balance between them.
Pretty cool and really only takes a few minutes of playing with it to figure it out.
Works the same way for the monitor levels and pan controls. M/S processing introduces some constraints since those channels are somewhat linked anyway, but I haven’t played around with any of that.