Hi, Ardour reference manual states: "Click the ‘g’ button to display a menu with a list of the available groups. Select one of these groups to add the track or bus to that group. Select “No Group” to remove it.
But, in Ardour 3.3, hitting the g key does nothing, nor I can find any “g” button… where am I wrong?
oops, found it, I was looking in the mixer window 
but, is it possible to add a track to more than just one group? For example, I want a group for all drums tracks, and a subgroup for overhead tracks, but I can’t find a way to do it
@ververlover: no, tracks/busses belong to 1 group at a time. there is no heirarchy. sorry.