new MRP procedure With New selection rule?

HI Gurus,

i have come across a situation the requirement is to configure a NEW MRP Type with NEw selection rules(REquirement Calluclation)

in the standard SAP system MRP Type is assigned with MRP Procedure by which the Behaviour of the MRP type will be decided. can any body tell me

what the scope of THis MRP procedure, and how can we configure new MRP Procedures according to our requirement.

Thanks&Regards,

Venkat.