I used to get bummed about seeing my family - I couldn't drink as much with them around. I never saw them as a trigger, just the opposite in fact.
You seem to be saying that your family drinks a lot together, and they have no idea you're trying to get sober? Are they going to force you to drink? Does your mom line up shot glasses and force all the kids to slam jaeger-bombs or something? Why don't you feel you can discuss this with them?
Perhaps if you tell them that you're laying off the booze for a while, they might actually be happy to hear it.