I think it's possible to choose not to be irritated. It does take practice, but the big advantage is that then you get to choose how you feel, as opposed to being manipulated by others to feel bad. Maybe have a script or mantra for the things that get you irritated, and use it to back away slowly from irritation to feeling comfortable.
This could be something like:
I can choose how I feel, and I have made wise decisions about this.
I am an adult and have made wise choices for myself to have no contact with people who have behaved badly towards me enough times to justify my decision. It is not surprising they don't see it the same way, and as I like to keep in touch with a sister who's in touch with them, I ll sometimes hear them mentioned, and she may sometimes repeat their greetings to me, or even make up greetings from them, maybe.
I can hear what she says, without letting this bother me, because it's her take on things, not mine. Maybe she needs to do this, despite I don't want to hear from them, and that's OK, it's about her not me, and I care about her.
I can choose how I feel, and I feel good about my decisions on this.
Or whatever applies. I find it useful with this kind of thing to think of myself as having a child part that's feeling upset or irritated, and consciously bring forward the adult me, so I can process from the adult part of me, not the hurt or frightened or upset child. You have already made a decision about this you are happy with, you don't have to feel bad about it , but a part of you needs reassurance, is how I think about this.