I play with a group that consists mostly of conservative Christians--it isn't a Christian music group but I'm in the wrong part of the country if I'm looking for left-leaners. Luckily, most of these people are not overbearing and the focus stays on the music (I'm sure it helps that the majority of it is instrumental, not sung).
I didn't grow up with a lot of religious music but there are a number of religious songs I do like ("I'll Fly Away", "Uncloudy Day", "Leaning on the Everlasting Arms", "It Soon Be Done", even "Wondrous Love"). If I present a song, it's usually something secular--Saturday, I'm teaching "Railroading on the Great Divide" and "Engine 143"--and if the group sings something that offends me, I take a bathroom break. I know that sounds chicken but I knew what I was getting into when I moved to Texas. I could sing "Joe Hill" all the way through by the time I was five but I wouldn't present it because a) it's a real downer, and b) the politics would go over like a lead balloon.
We have had to drop hints on occasion, though, that music club is not the time or the place for certain things; we followed the plan of publishing a general notice first in the newsletter, and then having the club president speak privately to some particularly persistent missionaries. They eventually drifted away and, as much as I don't like the idea of excluding people, I hope they found another forum that was better suited to their agenda.