How should I (31F) handle cliquey-ness with my female in-laws?

My husband (34M) has two sisters (36F and 31F) and two brothers (39M and 37M). Both brothers are married for context. Recently his youngest sister got married and invited one SIL but did not invite myself or another SIL to her bachelorette. I was told via my husband via his mom that I wasn’t invited because his sister doesn’t like the other SIL and I probably wouldn’t have gone anyways since I’m pregnant and it would have been too costly for us. MIL said that they couldn’t just not invite one so they didn’t invite us both. I honestly think that was an excuse. My husband’s family lives somewhat spread out but we visit them 1-3 times per year for a week or long weekend, and we’re not super close but I’ve never thought of us (especially in the last several years) as not having a positive relationship. I know that my MIL wasn’t welcoming when my husband and I first started dating. I don’t think she liked that I was more reserved and serious and wanted her son to marry someone more fun and outgoing. But my MIL seems to like me now and I thought we were all good. I know my MIL and husband’s sisters have all talked badly about one of the brother’s wife for years, so the conclusion I’ve come to is that they are cliquey. For context the brother’s wife is very nice but maybe just a little socially awkward and nerdy at times.

The difficulty I’m running into is how to handle my husband’s sisters acting like I’m not worthy of their friendship now that my husband and I have two young kids. Eventually our kids are going to get older, and I don’t want their aunts acting like they don’t like their mom. My husband’s family is very much a “we don’t talk about conflict” family, which I think exacerbates things. I’m frustrated because I feel like I’m open to friendship with them but they’re not, and it creates unnecessary discomfort for family gatherings. It also affects my relationship with my spouse, because I have resentment that he doesn’t stand up for me and goes along with them indicating I’m unlikable. We have a good relationship otherwise, but this is honestly starting to fester into something more long lasting. I’d appreciate any advice or even just a call out that I’m overreacting.

TL;DR my husbands’ sisters (and his mom to some extent) are cliquey about the in-laws in the family. One is the favorite and myself and another are not. How do I manage the relationship when my husband doesn’t stick up for me and now that we have kids?