If the building in question is a "church" then it is God's house. Denying someone its' use for any reason other than logisitics is wrong. Especially if the reason is "ya'll aren't members of our church". What Christian does that?
If its' a Christian wedding, surely some accomodation can be made, especially in this case.
If its' a Christian wedding, surely some accomodation can be made, especially in this case.