Status material

I'd like to put status 03 (Blocked for procment/whse) at the material, but I'd like to continue do transfer PO's for this material (only transfer PO's, not purchase PO's).

I couldn't do it, when I put this status at the master data, it's not possible to do transfer PO anymore.

So, could you help me? I'd like to block the material only for external purchase.

Regards,

Adriana