exit regarding md01 tr. for pp module

hi gurus,

this my requirement.

• Restriction of material selection during the MRP run.when MRP run is executed at

• plant level,material requirement planning is excuted for all the material in the plant.

• It is not advisable and may not be necessary to execute MRP run for all the materials

• in the plant,as materials may have different frequency for MRP execution.This exit is

• used in tr. code MD01.

*exit name they provide:M61X0001.

please help me how to achieve this.

thanks

sunhasis