For more clarification on the "group of family and friend" : A public performance is one that occurs either in a public place or any place where people gather (other than a small circle of a family or its social acquaintances). A public performance is also one that is transmitted to the public; for example, radio or television broadcasts, music-on-hold, cable television, and by the internet. Generally, those who publicly perform music obtain permission from the owner of the music or his representative. However, there are a few limited exceptions, (called "exemptions") to this rule. Permission is not required for music played or sung as part of a worship service unless that service is transmitted beyond where it takes place (for example, a radio or television broadcast). Performances as part of face to face teaching activity at a non-profit educational institutions are also exempt. We recommend that you contact your local ASCAP representative who can discuss your needs and how ASCAP can help you.
So, by that, a wedding would probably not be considered a "small" circle, but a house party is fine, I guess.