I don't think I pointed out.
When you split a hive and move one some distance, the old forgers will return to the old location.
What I usually try to do is move the one that has the queen and leave the queen less in the old spot.
If both have Queens it doesn't much matter.
How to tell robbing from, play flights or bees returning to their old home place.
The robbers will be very much more aggressive toward you and will be fighting with the bees in the hive that appears to be being robbed.
After a couple weeks when things has settled down, you can take a frame of capped brood from the strongest colony and give it to the week one, you know, kinda even up the score.
Just make sure you do this from the strong side you split from, not another colony.
Unless you know all the bees in your yard is healthy.
hope this helps some too.
I'll leave ya'll alone for awhile. ;) :)doak