Exclusion of sales orders/PO in PPDS run

Hi,

Is there any way to exclude specific sales orders from PPDS planning run (Heuristics)? (We have the criteria to identify those orders)

Is the check box 'not relevant for pegging' in product view, for the same purpose? If yes how to tick it ? Its in greyed out state.

Please let me know if there is some other way to achieve the same? Also we would extend the setting to other categories like stock and purchase orders.

FYI -- In ECC the SOs will be in open state.

Yogesh