Yes and no. I purposely keep status on two "families" (Star Alliance and Sky Team) for a variety of reasons. So I try to pile on USAir, as long as I keep a certain amount on NWA (which will be DL soon enough).
That said, when I select "multi-city", it treats it as totally individual flights, and prices accordingly.
That is, instead of saying, "Oh, you want to fly to OMA through PHX", it thinks I want to buy a ticket to PHX, spend some time there (even if it's just 45 minutes), then buy ANOTHER ticket to OMA. The site doesn't distinguish (at least the way I'm doing it!), itinerary-wise and price-wise, the difference between a layover and actually booking separate flights. (I hope I made sense in explaining that).
And, pardon being dumm, what's "ITA"?