Hi @Cameron_24323, and welcome to the Forum.
EDIT: @Cameron_24323 I added a second method 
Here two methods:
Method 1:
You could easily create a duplicate of your upper instrument for the full score (and put it into a group to avoid automatic renumbering), and write your desired rhythm notes on it, in a new voice, with accordingly high pitches, suppress the playback for those notes, and in Engrave mode hide their ledger lines. Then check only this duplicate for the full score, and use the original instrument 8without added rhythm notes) for the part:
rythm added to duplicate player for full score.dorico (594.7 KB)
Method 2:
Or you can create a dummy player/instrument to use for these rhythmic “cues”, and use the cues functionality on the upper staff/player, with cues shown for the full score (in Layout Options), and strategically hiding the “beat” cues for the part, and hiding the other “normal” cues for the full score:
rythm added to dummy cue player for full score.dorico (589.9 KB)
