Funds Management - Derivation - Matl group to Commitment item

Hi -

Can we derive commitment item from Material group. If I use table look up in derivation rules I can choose material group from MARA table to be assigned to FM commitment item. But I couldnu2019t figure out how to  achieve this. Is it really possible, if yes, please advise. Business requirement - we have budget for each material group but dont have equal number of GLs.

Thanks

Chris