Originally Posted by Craig6z

While not an answer for the OP, expanding on the Excursionist Perk option might be useful to other readers. Twice in the past year I've taken two one-way open-jaw awards and had UA combine them into a single PNR via the free add-on flight benefit between the two destinations.

For example:

• SFO-DUB Business Award on August 1 - PNR: ABC123
  
• BRU-SFO Business Award on August 12 - PNR: ZYX987
  
• Added a few weeks after the electronic bookings, a free DUB-BRU flight on August 7 and UA combined it into a single PNR (sorry don't remember which PNR they ultimately settled on).

This type of combination had to be done by phone, and the agent had to bring a supervisor in to complete it, so it took a good 20 minutes to process. UA has both times waived the fee for this, but YMMV.