Sounds like the pack is telling him he's being rude and needs to back off. Since you don't mention any altercations, it sounds like the pack is being very polite about it as well, though that doesn't mean it will stay that way if he doesn't change his approach. Walking them together may help significantly, since that gives them a group goal that doesn't leave room for insensitive play behavior. Also, making sure he's had some exercise before allowing him to try to play freely can take the edge off. If he's less excited, he's less likely to be pushy. Finally, I'd leave him on a lead when the dogs are playing together. If he starts to get too intense, lead him away and give him time to settle, and always praise polite behavior.
The rest of the dogs will likely accept his advances once he learns a little more self-control. It may take some time, though, since humans are more than willing to forgive over-excited, pushy behavior because the dog seems friendly (especially from smaller dogs), and view the dogs who enforce their personal space as rude or aggressive. The links below can help you recognize good and not-so-good social behaviors and how to respond appropriately. Good luck!
http://paws4udogs.wordpress.com/2012/...
http://drsophiayin.com/blog/entry/dog...
http://suzanneclothier.com/the-articl...