Be aggressive!!! Yes, don't let them set up shop. Hey, call a beekeeper in your area that removes swarms, or call 911 and the dispatch usually has someone, a beekeeper, who will come and get them. Swarms should never be killed, unless they have been there a very short time, and it would be impractical to take the house apart to get them out. Established colonies is an entirely different matter all together. Noone myself included wants to kill a swarm, but sometimes this is done over dismantling. I may catch flack for saying this, but this is the unfortunate truth. let us know your plight.
...JP