It might be easiest to create separate courses if the tees are significantly different. For example, naming the Castle Creek course as three courses: Castle Creek white, Castle Creek red, Castle Creek black. The advantage is that the next time you play the course on, say, the white tees, the hole yardages from the white tees are remembered by the Golfmetrics app.
Alternatively, you could have one Castle Creek course and the app would remember the hole yardages from the last time you played (and you’d have to change if you are playing a difference set of tees than the previous time).