You could equalize the hives as well. Pull some brood and put it in the weaker hives. That will HOLD your strong hive where it is, but will increase your weaker hives strength.
If you have five or six frames of brood, steal two frames to put in the other hives, if you have eight to ten, or even more frames of brood, steal 4 frames to put in the other hives. Just remember, that is going to be a lot of bees when they emerge. Your other hives will be boosted a LOT, while you try to maintain the big hive where it is.
I would also be pulling drawn frames from that hive.. Meaning, frames that have nothing much in them YET, but drawn comb, and replace with a foundation frame for them to draw. Keeping the bees employed, and having room to expand with more boxes goes a long ways toward swarm prevention... But, it will impact honey production.. that is where a little experience pays off, knowing how far to go depending on the strength of the hive.