Flight number sorting [neointerface!Quimby]

Perhaps I’m just blind and/or unfamiliar with the interface layout, but has anybody seen a way to assign flight numbers to a group at the route level instead of manually ticking the flight numbers and sorting into the group? I see the route setting for prices/service, but not custom flight number groups.

As in, all flights YYZ <-> YUL are defined as custom group ‘Eastern Triangle’ so any new flights scheduled don’t have to be sorted to that group once I have the funds for more aircraft and can schedule more flights.