Should be allowed, but it's very hard to find a rep to manually price.
They have to agree that's valid and then call the rate department to manually price it.
CO ESD may be the best bet, but YMMV as reps there are either horrible or awesome.
I was recently able to get an ESD rep to manually price this EWR-HNL-LIH (destination) (open jaw) OGG-LAX-LAS (stopover) LAS-EWR.