store values in group

Hello All,

I have a reqmtn and this is specific question,

Wht i want is that i have few grades on R/3, and user wants a report in this grades,

BUT the relation of grade to grade group is set up by user, IT does NOT exist on core, so i want to knw wat is best construct to store temporarily grades in grade groups in my program, there are lot of grades and user doesnt want to store grade groups on R/3, type pool wud help?

please advise,

Thanks,

RS