You could also blockade one of the ways with an invisible object
What happens to the next minion on the same path.. if it needs to take a different route?
How about if we could have multi target.. and assign certain sequence..
say minion1 = targets (1,3)
minion 2 = targets (2,3)
so that way minion1 would take a different route collecting target1 and then target3 .. than minion2 that'd take 2 first and then 3.
Eventually both reach 3 in different ways. (ofcourse the way you place targets 1 and 2 matter)