Override function in Hyperion Reports

question: any ideas how to do something similar like the override function in WDEF's in FR reports?

example:

for rows 1-50, in all columns "TotalC1" is used

for row 51, in first column "C1Member1" is used, in the second column "C1Member2" is used etc.

the ideas I had so far was using multiple grids or use hidden rows/columns and formulas. but both is not really user friendly.

Thanks jana