[Torin]

It was always this way i think. They are suppose to join call of the wild and the such.
The trick is to get some stealthers like woodsmen and reinforce them with summons.
Llamabeast said the procedure from now on.
The other trick is to cast ghost riders and then call of the winds, wild or the such.
Also ghost riders can attack along with horrors and the phantasmal attack (anonymous), and the rest that are not anonymous can join together.
edit: I wonder what happens if you cast ghost riders in the same province that other player has cast ghost riders too. Probably they join.