M.L.
Consider taking her with you in a carrier. She'll probably sleep most of the time, and if she does wake unhappy, you'll be able to soothe her right away.
We took our newly 1 year old to my husband's reunion and it went perfectly fine. There were other little kids (I think ours was the oldest) there as well and nobody thought or said anything about it. At six months old, both my kids also were held or carried most of the time. That's what they needed and was absolutely the right choice for our family.
If you really want to leave her, then one thing you can try is having your husband soothe her and offer her your milk every night between now and the reunion. That should give her some time to prepare, but she also may become more insistent on you during the day. She's right at the age of seperation anxiety.
Another option to consider is for you to not drink (I don't assume that you will, keep reading) and then if you are needed to rush home to baby girl, you're in a position to be able to and then still go back to your husband and the reunion. It might be terribly inconvenient for you and your husband, but it might be want she needs.
I just read through the other responses and can see that mine is much different. What is your gut telling you is the best approach? You're the mom and what your gut is telling you is probably right.