Currently there are three types of fortifications.
Adjacent: You can move men from one territory to a territory directly connected to it.(One move only)
Chained: You can move men from one territory to a territory connected to it in a chain. (One move only)
Unlimited: You can move men from one territory to a territory connected to it in a chain. (Unlimited moves)
My Suggestion
#(2-5)* Chained:You can move men from one territory connected to it in a chain. (# (2-5) Moves)
* There would be an option for 2 chained, 3 chained, 4 chained, and 5 chained, and possibly more.