I attend a Saturday morning dog play group. I bring all of my kids (2 dobes, a Border Collie, and a Border Terrier). There are usually 15 to 20 dogs that come and go over the course of about 2 hours. My guys are very well socialized, they attend day care everyday and are involved in flyball, agility, and obedience, so I'm not overly concerned about fights. However, everyone is very vigilent about watching for any aggression and we nip disagreements in the bud.
But things do get rowdy. Everyone is chasing afterballs and jumping all over and each other and having a great time. My concern is the little dogs that come. I'm thinking in particular of this adorable Yorkie and his brother (can't remember breed name..about 10 pounds, wht/blk with long hair and fuzzy pointy ears..really cute). These guys are as rough and ready as everyone else, but I cringe when they get into the middle of everything. My 2 dobes and a rottie are the biggest dogs there. Should I be trying to keep my guys away from the little ones or just trust that the owners know that their dogs can handle themselves. They just seem so fragile, I love having them at group because of their personality, I'm just wondering if I should we suggest that we divide up by size.
This may be a little off your topic, but wanted to post it anyway. Depending on your location, be aware of the canine influenza that is going around too. Right now there is no protection, even though they are working on a vaccine. So keep that in mind when you are at playgroup as well. Always something has to rain on a parade!
This is a hard one. I say it is a shared responsibility. Since everyone seems to be resonsible, from your description, it is up to you to know if your dogs are getting too rowdy and up to the owner of the small dogs to know when they are being overwhelmed.