Tire rotation of just two tires?

Hello,

I have a 2002 Hyundai Elantra GT. I've noticed that two of my tires lose air frequently in the winter but just one at a time each winter. My tire guy said the wheels are rusty so they've lost some of their seal. They seem to lose air only when they're on the front axle. I'd like to put the two that lose air on the back axle so the good wheels are on the front. Currently, one bad wheel is on the front drivers side and the other is on the back passenger side. Can I rotate my front driver side wheel with my rear driver side wheel and leave the other side alone? I have good tread left on all 4, the tires have about 20,000 miles on them and they were supposed to last 60,000 miles I believe when I bought them 2-3 yrs ago. I plan to stop rotating them at this point so that I can avoid putting extra air in one of them every winter. I looked into replacing my wheels but it would be too costly. Thanks