Cannot Attack Monster Lair Due to Caravan Being 'On Top' of it

Hey all,

The title pretty much says it all.  I keep preparing to attack monster lairs only to find that there is a caravan on top of the lair tile and I cannot right click to attack the monster camp that is in the square (or to move onto it and loot it if it's empty).  I wait another turn and another caravan appears there!  I wait yet another turn and yet another caravan appears!  It can sometimes get to where I have to wait 6 or 7 turns to clear a particular monster lair due to this annoying bug.  Is there any way I can get around this short of declaring war on the faction who owns that caravan and killing it?

Thanks!