How To Do Multiple Loops Through A Cursor

I have a table where each record has a numerical x-coordinate value as one of its fields. I want to loop through a group of the records that have another field in common in a given order. In a nested loop, I would like to subtract the coordinate of the outer loop from the coordinate of the inner loop for all records in the inner loop that appear later in the sequence. The result is a list of the distances between all coordinates.

Example:
x-coordinate
3
4
6
7

It would look like this:
4-3, 6-3, 7-3,
6-4, 7-4,
7-6

I can do this using two nested cursors that select the same thing basically. But the table being selected from is pretty large and it takes forever to keep selecting from the huge table when the inner cursor could just copy the results of the other cursor and repeatedly iterate through them.

Is it possible to copy a cursor's results into another cursor or reset the cursor index back to the beginning so that it doesn't have to do the select statement every time?