iPhone Sync and Last Played Date Question

[chip7037]

My wife and I both have iPhones and we both sync with the same computer. I like to be able to listen to different songs without repeating old ones, so I have an automatic playlist which will only display songs that have not been played in the last 6 months. The issue I'm running in to is that when I sync my wife's phone any songs she listens to update the last played date, and thus throw off my playlist. I know an easy answer would be to sync her phone to a different computer, but I would like to avoid that. Is there any way to setup a one way sync so that certain devices will not update the iTunes library? Or is there a way to temporarily disable library updates that I could do whenever she syncs her phone?

I realize this is a trivial problem, but I thought I would see if anyone on here had suggestions.

Thanks in advance.