What rib patt are you doing? K1P1? K2P2? Something else?
If K2P2, you could easily work 2/2 cable. Put 2 sts (over the K2) on cable ndl, hold to front or back...depending on which direction you want the cable to twist...work the first 2 sts (over the P2) on the left ndl and then the 2 on the cable ndl.
Is that what you were looking for?