I think I'm okay on this, but I want to make sure.
My parents are each giving us some money for our wedding, although we are paying for the bulk of it. FH's parents have both passed on, but we are close with his sister and her family.
We would like to include them in our invitation language by saying "together with their families", as long as that doesn't imply anything untoward, like we are expecting money from them or something. We aren't. We just want to acknowledge my parents' contribution, and the fact that we are getting married with the support and love of both families.