Parent friendships and DD’s school friends - how do I handle this?

[woollycat]

DD (6, Year 2) is in a tight-knit group of four girls who've been together since nursery. They're very close but also clash constantly, so it's a real love-hate thing. One day they're best friends, the next someone's upset or left out, and then it's all fine again.
The parent side is making it harder. I've always been the one organising playdates, and it's rarely been returned:

mum A: I've hosted her DD several times. She's never invited DD back (apart from once when I had a last-minute emergency and she had no choice), and she often cancelled or rescheduled. Then DD asked A's daughter about a playdate and was told "my mum says you're not a good friend so we can't have playdates." DD was upset and so was I.
mum B: Friendly and helpful with school stuff, but in all this time she's only invited us back once. I stopped initiating a while ago and she hasn't suggested anything since.
mum C: Has happily accepted every invite but has never invited DD back.

Meanwhile A and B are close friends and their girls have regular playdates together, so I can see DD ending up on the edge of the group outside school, which won't help with all the clashing inside it.

So:

Do I keep making the effort for DD's sake, or step back?

Has anyone dealt with a parent apparently telling their child not to play with yours? Did you say anything?

How do you help a 6-year-old through an on-off friendship group without passing on your own feelings about the parents?

Encourage your daughter to make friends with other children at school and elsewhere. Maybe neighbours, children you meet at the park and at after-school clubs etc.

When it comes to friendships, these girls cannot be your daughter's whole world.

Doesn't sound like a very healthy friendship anyway, and if they clash more when your DD is involved then probably best if everyone encourages new friendships outside of the group.

I wouldn’t be encouraging these friendships, stop facilitating it with play dates that are never reciprocated anyway. Sounds like the parents are using you for free childcare and don’t care about your daughter’s feelings. It can only get worse, encourage her to play with someone else and withdraw from these users.

Oh I think I recall this. Isn’t one of them a ring leader and leaving DD out? And you have play dates only on weekends?

100% the situation here. The parent cliques made such a big difference to our primary social bubble. What is absolutely BRILLIANT is that these have all dissipated upon the kids getting their own phones.
The kids all just socialise with who they want to socialise with. It made primary a nightmare but secondary, so far, has been brilliant

no, not my case

https://www.mumsnet.com/talk/primary/5579240-would-you-raise-concerns-about-a-possessive-friend-in-year-2

so similar to this!