I put my tup and wether in with the ewes carrying singles a few weeks ago. There was a bit of fun (mostly the wether, who was completely over excited at being out "in company") for about half an hour, then they pretty much settled down.
However, I did buy another trough to make sure there was loads of space at feeding time and a 10ft covered hay rack (for nine sheep) and there's no pushing and shoving there either.
Not sure about a group of tups and I'm not brave enough to put him in with the ewe hoggs, who are in with the twin bearing ewes.