[The Finn]

Perhaps interception could be based on a percentage chance.. could base it on the average speed of the forces involved, or on the number of 'fast' type units perhaps with additional modifiers if the interceptor has scouts or astral paths in his army.

As for what happens when an army breaks and enters 2 or more areas, the interceptor only intercepts one. It's the easiest to code and it would allow the breaking armies to still wage an offense - with the good possibility that a portion of their force would be destroyed. It could even be a tactic - dispatching a small force with retreat orders hoping to sucker the enemy into chasing them while the main body marches forward.

Personally, that sort of tactic appeals to me.