Well, I can only go by my experience (and it's limited). I tried a male in my community tank, with a back-up should things turn ugly. Luckily I appear to have landed myself with a total wally, as he isn't aggressive at all and spends most of his time avidly studying the two frogs. He seems particularly fascinated by their feet...
I introduced three ladies for him, and increased them to five after reading here that more females = calmer females. That has proven the case, as when I had three, one became a total ***** and nipped the others, now there's five they just don't bother. Also, the male isn't bothered about them either and neither harasses the other, although this cannot be guaranteed with different fishy pals!
But
it all depends on the fish, which is why you need to observe and have a back-up plan, just in case.
I ran into trouble because my golden gourami took against the influx of female bettas in his patch and became aggressive to everyone (except the shark, the wimp!), so I found him a happy home in a gourami-only tank at my lfs, and peace was restored. But others have found gouramis and bettas peaceful companions.
Not overly helpful advice I suppose, but best I can give! All I can say is my set-up below is very peaceful of late, so it can be done!