announcing #2 help

So my husband and I were thinking of announcing to our family on thanksgiving or even waiting until Christmas. we are due June 6th. I wanted to wait until my family could be in town to announce it to everyone. my mom threw us a curve ball and told me yesterday that she will only be able come up for our Dd's 4th birthday in the middle of November. so we are now going to Announce early probably during her birthday party when the family will be all together. I need suggestions on how we can surprise the family but not take away from my daughter's birthday. (please note we only do cake and presents for her birthdays also it's just the families that come)