The key to what you are asking is to remember that a JMP data table is NOT a spreadsheet. What I would suggest is to transpose your data table and then add a new column of differences. Then you are set to analyze the difference by the groups that you currently have in columns.
1. Table > Transpose
2. Select your label column as the "Label" and select all other columns and click "Transposne Columns" and click ok.
Now you have a new table with a column of labels for your "groups" (what were your columns) and two colums of data, one for R1 and one for R2.
3. From this new table higlight the two R columns, right click, select New Formula Column > Combine > Difference.
Now you have column of differences and you can analyze how the differences differ across your groups (i.e., use graph builder with the group lables as the x and the differences as the y).