Larger colonies are not more pissy. The only thing that makes a hive pissy are:
1. Genetics.
2. Irritants
Deal with genetics by requeening from a known source.
Deal with irritants by;
- giving time to adjust to major changes or short term disruptions that have been done by the beekeeper or by the environment
- beeing observant of recurring pests and conditions around the hive that affects them, and take action to eliminate/minimize those irritants. Those pests/conditions may be IN the hive or the environment around the hive.
Changes were made to the environment of the existing hive and to the colonies that were brought in. In this case, the fix is time. 1 week should do it.. If you have neighbours and kids and wife garden so close that time is not possible, then I have to be blunt and up front to say that you should not have any hives in that location, not even one. Even the best calm hive may have a short flare periodically. If that cannot be tolerated then the solution is no bees at all.
PS: Young bees are much more gentle. It is the old tired worn out bees that can get pissy ... again only if genetically disposed or irritants are present. Keep this in mind for when a "new" calm hive becomes mean 2 weeks later. The reason splits and cut-downs can work is that is usually done with nurse bees and capped brood = young bees. The original hive location where the old bees return too may continue to be knarly until those die off. The cut-downs may also become just as pissy 2 weeks later as their bees age as well.
PS2: Also know the difference between bees flying around as being defensive/aggressive vs bees being disoriented and seeking out their new environment. When I move a beeyard of multiple hives to a new location, it is utter chaos for about 4 days. Bees everywhere zipping in every direction as they get oriented, searching, and finding where the new forage is. During this time it can be un-nerving standing in the middle of the yard. Bees that run into you full speed may instinctively sting. I will not enter the yard without a suit. Go back 7-10 days later and the yard of millions of bees is hard at work, flight is orderly, and they could care less that I am there. I will walk in shorts and t-shirt and pop a few lids with no concerns.
So, give them some time and see what happens. After giving them a reasonable amount of time (7-10), then take whatever action is necessary if it is still a problem.
Hope that helps!