ANSWER:

No problem in this as long as its not something exclusively done by non muslims and there is no music, free mixing etc.

QUESTION: In my country, on marriage day, the cousins of the bride blocks the groom on ceremony gate untill he pays them some cash. They do it out of fun. This has become a culture now, even sometimes the groom comes prepared to give them money. In my sisters marriage, eventually the groom gave money and I received a portion from that without realizing this could be wrong. Can I keep the money?