What I've been doing is:
1) Select all clips you do NOT want to see or edit in PRV then Right Click > Mute/Unmute or simply press K on the keyboard
2) Select the clip you DO want to work on > Right Click > Views > PRV or double click the clip (if you have double click set to open PRV)
3) In the PRV context menus (top of the PRV) select View > Hide Muted Clips
Now only the notes in the clip you have selected will be in the PRV.
However if you are going to add NEW notes to that Clip, depending on the mode you are in, what may happen is the new notes will appear in a new lane and the Lane (not the clip)will possibly be muted so you won't hear them. If you have Lanes open when this new clip is created you will not see it and won't be able to unmute it. To fix this simply close the lanes and reopen them again and unmute the lane. I think this may be a bug or things getting screwed up by unintended behavior.
After you are done editing bounce the new clip with the original and they should merge.
Using Overwrite mode (from the Record button options) may put the notes directly in the clip you are working on but I haven't tried it yet and I'd rather keep my new data separate until I bounce anyway.
Cheers.