Data fields that computes based on different datums

So you can select the datum that your coordinate system calculates from. Can you have multiple data fields that calculate on different datums?
For example:

4 fields,
Field1=Datum1
Field2=Datum2
Field3=Coordinates based on Field1 (UTM/GMRS/LatLong)
Field4=Coordinates based on Field2 (UTM/GMRS/LatLong)

Is this possible? Thanks in advance.