The couple that I go to, you can bring intact males.. you just aren't allowed to bring females that are in season. I think the age limit is at least 5 months, but I started to bring Sebastian at around 4 1/2 months because he already had all his shots, and he was big enough by then that people thought he was well past 5 months old, hehe.
I used to take him to the dog park every day, but now that he is becoming more of a "man" I have backed off. Since he is not fixed yet, I started to notice him growling a little at other intact males. I don't think he would actually start any kind of fight, but I'm not so sure about the other dogs. He has had his fair share of dogs trying to attack him, whether it's because of his size, or the fact that he still has his man parts, I don't know.
Maybe trying taking him to the dog park once and see how it is. The worst that could happen is someone telling you he isn't allowed and you have to leave. Are there people there monitoring it? Because I know at mine, there aren't.. it's pretty laid back.
We also have an outdoor mall where I live that allows dogs, so I take him there and walk him around. He doesn't really come in contact with many dogs, but I want him to be used to being around lots of people as well. Is there anything like that in your area?
Just a mention as well, Sebastian absolutely LOVES small dogs.. he is very gentle with them when he plays with them.. maybe try to introduce Bailey to some of the small dogs. It's actually quite a funny interaction to watch.. I still think Sebastian isn't quite sure what kind of creature they are, haha