PO flow to APO using EXIT SAPLMEAP 001

Hi Gurus,

I am having trouble in understanding how to restrict the PO flow to APO. So my guess is IT_INPUT and IT_INPUTX in EXIT SAPLMEAP 001 holds the required data. So should I loop them and delete entries that do not match my criteria ? or should append the same to IT_OUTPUT and IT_OUTPUTX. Kindly help me in understanding this.

Regards,

Krishna