How to manage bazillion armies in the campaign map?

In our current co-op campaign, we've come at a point where we have like 20+ armies on the campaign map on different frontiers.

It gets pretty difficult to keep track of all of them and very frustrating.

Is there anyway I can tell 3+ armies to go rally at a certain location without needing to select them 1 by 1? If none, is there any mod that does this?

The microing is taking forever