engagement party during sefira

Question

harav- assuming i observe the first set of days as my minhag sefira- would it be permissible to attend an engagement party thrown by a friend? i do not mean an informal "get-together" of a few friends marking the occasion; i am referring to a formal gathering whereby a large number of people (neighbors, family, friends, parents' co workers, etc.) are invited? i do not know if there will be music there. thank you.