The group variable just allows the user of the function to select which
blocks of array elements they want shown in a particular cell.



Using column  headers of 1,2,3...10 with the alphanumeric strings listed
down a column, the user can fix the header and row references to extract
the different blocks of characters within the strings.



Using your example [123XYZ24], group 1 would correspond to "123", group
2 corresponds to "xyz" and group 3 to "24".