Grandparents don’t get along..

So my daughters 1st birthday is coming up.. there has been some tension between my mom and my SO’s mom.. so both told me they don’t want to be around each other.. well her birthday is next month and me and dad don’t want to give separate parties.. we feel like two grown adults should be able to ignore each other and come together for a baby they both love so dearly.. so his mom wants to give her a separate party and my mom does as well and we both don’t want that.. it’s so hard to even plan what to do bc these two immature grown adults can’t “be around each other” I mean am I being unreasonable? It’s a baby’s party for Christ’s sake and I’m so stressed out at this point because all I want is for everyone to get along and that’s now ruined 😕 my mom makes treats as well and she said she isn’t making any treats for the moms party but she will make them for hers. I feel like they both are being immature.. I don’t even know what to do