We use that phrase in AA, too.
It means that when you listen to other people's shares or their stories, don't compare your situation to theirs ("Oh, I can't be alcoholic--I didn't drink like her or didn't lose everything like that guy" or "Wow, I drink a lot more than these people, maybe THEY could get sober but I'll never make it"), but listen for the ways you are like the other people ("Maybe he did time in prison and I never even got a ticket, but it's amazing how much the way he felt about drinking is just like the way I feel"). Look for the ways we are alike, not different.
Alcoholics (and partners or children of alcoholics) have a lot of very similar experiences, even if their stories aren't exactly the same.