Given a rectangle R containing P points, orthogonal with axes, points are natural numbers.
Parcel is a rectangle which:
I can think of a backtracking and exponentially hard method for starters. You pick your points in some order and each time do either of the following:
1- Decide to pass a vertical line 2- Decide to pass a horizontal line 3- Decide to ignore
Until you end-up with 3^n different cases.
For your own application, you could think of applying some bounding conditions at each iteration, e.g., verify if you have ended up with a parcel with no point inside, then backtrack.