I'm going to hang up on a conference call with my family because they didn't like me disrupting the call by reprimanding my kids
Why does that make you want to hang up on them?
I don't want to listen to their crap.
Even if the conference call was inconvenient for you with your kids around, it was an important way for your family to keep in touch all at once.  You shouldn't hang up on them or ignore them entirely, just try to excuse yourself if you need to deal with your kids during the call.
It's their fault for calling on a Sunday when I'm with my kids. What would they expect?
I understand what you mean, but I don't think you should hang up on your family when they want to talk with you. Maybe you could try muting the call when you reprimand your kids, or let your family know that it would be better if they called at a different time.