You can definitely prune them and root the tips. I wonder if it is possible to sort of air-layer them?! I saw a pic of Adeniums in Asia with damp paper wound around the branch and tied . I tested it on my large jade: 1.5" trunk. I wrapped some Saran Wrap too over paper and loosely tied. And then Dribbled water from top ev few days to reset the paper. And i got roots! The reg air-layering with moist sphag might rot the branch, but this can be nifty for layering nice triples off the top safely.
