Pack of 3 dogs split up through divorce. Is it worse to allow the dogs to reunite every couple of weeks?

My ex and I had three dogs together (two Labs - Chloe and Roxie and a little mutt - Chili). When we split up we decided that he would keep both Labs (as Chloe is blind and I didn't want to worsen her abilities in a new location) and I kept the little dog when I moved to a new home. On occasion my ex needs to stay away overnight because of his work. On those times I gladly dog-sit for our two Labs as he drops them at my house on the way to his overnight work requirement. Chili is always so happy to reunite with Chloe and Roxie but I wonder if this reuniting and then "gone again" scenario is helping or hurting Chili. He has obviously been grieving since the pack split and once the other dogs come and stay and then leave he doesn't seem anymore depressed than he usually does. When he is with Roxie and Chloe, Chili is the pack leader. But once they leave he becomes a follower and allows me to be the pack leader. Is this scenario doing Chili more harm than good or is it good for him to know his other dog friends are still out there and will visit from time to time?