How can I make unsocialized dogs comfortable in a playgroup?

I'm starting a small dog playgroup. It's very likely that many of the dogs will be unfamiliar with playing with other dogs. How can the members make their dogs comfortable, and how can we avoid aggression?

Socialize them slowly. Don't just throw the dogs into that situation, because it could stress them out and cause them to act aggressively. Introduce them on leash and let them sniff each other. Its best to do it one on one so no dog feels overwhelmed.

Start small, start gradual, and don't force them. Allow the dogs to sniff each other and get used to the other dogs before starting activities. Make sure that the humans are relaxed too. I hope I helped.

bring your dog for walks with the other dogs & make sure they are on leashes and have muzzles on they eventually the dogs will get used to being around other dogs

You really should know what you are doing before starting this up.I don't even like puppy play groups if not supervised by experienced knowledgable people. Some of these "free for all" play group type things do not teach a dog good manners at all. A dog should only go visiting and playing with another dog on the say so of the owner and not just because it is in a play group. I would much rather see obedience class or social get together where the dogs have to sit near their owners and behave. Far better for the dogs.