single iDOc to multiple files based on a condition

Hi Friends

need your help in one scenario which is something like this:

there is one iDOC as the sender and this iDOC has to be mapped to files based on a condition means let us say if there is a particular field "R" in iDOC(WPDBBYY01) than it should go and create the file "ABC"

and if the particlar field is P or G or M than it should create another 2 files named "XYZ" and "WUV" .

Please guide me how can i put this condition ?

Any help would be rewarded with points

Thanks