I had to tell a couple people not to call me while drinking, and then just decided not to answer the phone on days I suspect they are (days off etc). Unfortunately, I don't have enough people to talk to and get very lonely, so I will talk to them when they are sober.
The trigger was almost impossible to overcome. Oh, wait, yeah, I had to tell them that after I went back to drinking after one such incident. So I'd say for me it was impossible to overcome.
At first they were mad, and thought I was blaming them for my drinking. Eventually they came around, and it didn't take long when they realized I was serious.