You can.
I made a dummy booking (ANA award). However, I can't any availability for DEN-FLL
But, I made successfully the following award (just before final ticketing/mile deduction phase).
01NOV UA550 ORD-SFO
08NOV UA756 SFO-DEN
15NOV UA1613 DEN-LAX
30,000 miles(Y) and 1860JPY
Sometimes, it becomes an error at the ticketing phase.
But, the rule permits two stopovers and origin open jaw within a country.