Some people have them extra large "get along" shirts for when their kids misbehave and need space but we do it different here and we have found that when my kids are not being forced to "hug it out" or sit in a oversize shirt they figure out their problems way quicker and better. Now let me say no, not every kid is the same and that big shirt might work for you but if it is not try something like this.
What we do is set up hunts. Some lead to treasure (if being rewarded) some are just for fun(maybe leading to a park for some play time). Some things they do separate and some things they need to do together to move on to the next spot/clue. It might take a few moments to write out clues but watching them figure out how to solve their problems/disagreements is rewarding. It gives them skills they will use for a lifetime.