I'm sick of women talking about salary over drinks

I try to avoid my coworkers when i'm out just because i want to have some separation between work and personal life. Or at least I try to. My company is very small, and I live right next to the bar/ restaurant where everyone meets up. I basically get dragged along and if I say no am politefully told that I'm a loser who doesn't leave his room unless he has to. Frustrating, but not uncommon, right? This isn't even my vent, or what I have a problem with. It's what frequently goes on when we're drinking that gets me down. Nearly every time we go for drinks, the topic of salary comes up between my only 2 female coworkers. They're the only 2 who make real money, I make $15 an hour and the other guy makes $20. We all have the same position but apparently the 2 females have very different salaries and are in the process of getting them changed. Cool, I'm happy for them. The problem is anytime the boss is around its all they'll talk about. Even when he isn't there they still talk about it. All they ever want to do is compare themselves to us men. Frustrating to say the least, but I've learned to deal with it. What really gets me down is anytime we are out and run into someone we know, the first thing these women do is ask what their salary is. I've seen it go from "how have you been?" To "what's your salary?" In a matter of minutes. I've seen women I've known my whole life, friends of my family, even fucking professors I had when I was in high school get grilled about their salary by these women. Most of the time its just me and these 2 women out so of course they're making new friends at the bar and as soon as they do its like they need to know just how much money they make. I've seen countless women get embarrassed by these 2 women over this topic and its fucking frustrating. I don't know how I would even go about mentioning this to them, or if I even should. Its just so fucking frustrating and I don't know how they can't see how fucking awkward they make it. They frequently make jokes about how they're going to ask everyone at a party what their salaries are. Information nobody needs to know and nobody cares about, yet they somehow think its fine. I've seen countless women get embarrassed about this topic and I finally need to vent about it. I just don't understand how they can't see how fucking awkward and rude they're being.