Match everything except "/"

I have a pattern like:
SOCPattern\* pattern = [SOCPattern patternWithString:@"groups/:groupId"]; // valid groupId is of the form group:domain:identifier. Example: group:mydomain:12345

BOOL conform = [pattern stringMatches:@"groups/foo/users"]; // conform is YES

I want the :groupId to match everything other than a "/" so that the above returns NO. Is it possible?
