I dont understand the problem: If theres is no place in thise bags to get out (for example to arrive the goal point) the Pathdinding should raise the used cost as high as needed to get to the point. At fist in searches for the lowest cost, but if theres no way, it uses the next higher costs etc. Am a bit surprised that your units hang there. Shouldnt happen with a normal a* or djikstra o.O