Interesting thing is they can see each other from day 1 if arriving here. Brood 1 and 2 are in my sewibg room with brooders next to esch other. So they have been seeing each other all along).
That probably counts as see-don't-touch
I would put both groups in the new coop at the same time.
No territoriality issues that way.
Still use multiple feeder and water stations and some 'clutter'.
I have had excellent results by following @aart's advice on many aspects of chicken-keeping.