How would you navigate this?

For context, we're all mid 20s to early 30s.

When 2 people are not good friends, how do you decide who gets invited without ruining the other friendship?

My partner has a friend who doesn't like another girl - they used to be friends and had a falling out. I'm wanting to throw him a surprise party but not sure if I should invite them both and let them know the other person will be there, or pick one person, or invite neither and maybe celebrate separately with each of them (EXHAUSTING LOL).

They're both outside our typical friend group so we don't see either of them very much, but my partner is still good friends with them both. I don't want to step on any toes or cause him to lose a good friend on either side. What do I do?