Moon, frankly, it's your fault. You. Let. Them[0]. Get. Away. With. It. When they are called up on their rota and they say they can't do the call out when it's their turn for whatever reason so management call you because you're soft enough to take up the slack. Next time just tell them to call the on call person because you aren't at home, you are with others at a social gathering[1] and it is not convenient and are miles away from your gear and it would take hours to attend. Sounds like a good time to plan a meeting with your boss and tell him that you are fed up with taking the majority of on-call calls when it is not your turn and you will only do your rota from now on and stick to it. Any newbies have to pull their weight and you can't continue to cover for them and it's not fair. You have to be firm on this and it won't happen overnight. Your managers need to manage, they aren't doing this. Learning to say "No" is a skill just as important as any other. I had a notice near my desk which said, "I have the right to say "No" in the following circumstances: 1. I don't have the skills. 2. I am busy and my tasks have a higher priority. 3. It is not my problem, it's yours." You get my drift and I'm sure that you can come up with some reasons suitable to your situation. You need to make yourself gradually less available when it isn't your turn to be available. Lie, if necessary. Say you are out even if you are not.
[0] The other employees.
[1] Whether you are or not.
Good luck. I had to do it but I had some encouragement from management as I was spending too much time doing things that were pressed upon me that weren't my responsibility. It was a goal set to me in one of my 1:1's as, like you, I couldn't say "No". Sorry your situation is what it is but you CAN manage your way out of it gradually. Take time and think what you have to do.
P.S. Don't tell me that I am using too many "ands" in a sentence. I know my rules of grammar and have done it for a reason - to sort of emphasise and bring the items to your attention.
Oh, Moon, tell me to bugger off if you like. I wouldn't blame you.
![Rolling Eyes :roll:](./images/smilies/icon_rolleyes.gif)
I believe in offering every assistance short of actual help but then mainly just want to be left to be myself in all my difference and uniqueness.