Nope, can't. See, you can't trade consecutive picks, so consider the following scenario:
DAL owes OKC their pick protected 1-20, trades the same pick to TOR protected 21-30.
DAL's pick ends up 16th. Protection means that DAL moves the pick to TOR, and DAL owes their next year's pick to OKC. The next season's pick ends up 25th, protection doesn't apply, so the pick gets transferred to OKC. Because this is a possibility, the dual trading of picks is not allowed.