Cermiestar> There is one piece of advice, though it’s not at all very party-ish.
Go to neither party. Tell your two friends, that you simply can’t decide (which you can’t), and to avoid any problems, you won’t go to any of the parties.
Perhaps your two friends would then realise the problems they’re giving you?
If you definitely want to go to one of the parties, it should be #1. If friend #2 said she wouldn’t even invite you there you go.