Your original will be the normal G54 offset, all you need to do for any others you wish is use another offset, there are 254 of them to use.
If you go to the Offsets page you can choose the first six directly, simply jog to where you want the zero position to be, click for example G57 and then zero the axis. If you again click G54 you should see the DRO show the position the table was at before you zeroed, press G57 again and they should again show zero.
You can do similar from the MDI line, to get the higher number offsets you type G59 P123 (The number after the P is the offset you wish)
After you have the offsets stored you can then call which offsets to use either from MDI or preferably from your first line in the code.
Hood