The Children's Hour

Many of you already know about the quandry of which I am about to write, but I figured that I would post it anyway just to reap some advice if you're willing to be forthcoming.
Adam and I have some good friends in our lives who we see from time to time--maybe 3-4 times a year when either of us is in the others' town (we don't live very far from each other). We've known these friends for many years now and get along well with them. The problem is...their kids.

The kids' behavior is pretty much abysmal. In the times that they've been to our house, they have jumped on furniture, broken a screen door, hit other houseguests and nearly knocked food off the table. The even bigger problem is our friends, as they seem to turn a blind eye to their children's behavior, almost as if they expect us to parent for them. It has gotten to the point now that Adam and I have collectively decided that their children are no longer welcome in our house, which is difficult because that means their parents will no longer visit us either.

The last time we saw these friends, another houseguest who was over at the time told me later that she was in disbelief by the children's behavior and was angry on my behalf. I was glad that someone else noticed the ill manners and had the same reaction I did; in fact, several people have pointed out to me on occasion the poor parenting of these children. I just don't quite know what to do about it. Obviously, if I approach the issue with the parents, they'll be offended and I risk the relationship...but as one wise friend pointed out to me, these friends are not respecting us by allowing their children to run hogwild through our house, tearing things up and disturbing guests and animals, so why am I worried about hurting their feelings?

I know she's right, but still...I hate to lose a friend over something kind of silly. But then again, the two hours Adam spent fixing the broken screen door wasn't very silly for him.

What do you guys think?