Control OP and OT Order Quantities?

Any suggestions for forcing OPs' and OTs' order quantities to be a multiple of a specific order quantity by item? e.g. Set up multiple order quantity for item ABC = 10. Purchasers would be prevented from ordering any quantity of that item that isn't a multiple of 10. I know that MRP, if configured correctly, will use the Multiple Order Quantity field to suggest orders in multiples of the MOQ and will round up to the next multiple, but we're looking for a way to force that logic during manual OP and OT entry.

Hi Tony,
I think you can set up (for item ABC) unit of measure BX that equals 10 pieces (1 BX = 10 EA). Subsequently you can set up BX as purchasing unit of measure. Then using security you can disable possibility of changing unit of measure when entering purchase order.
In consequence user can enter purchase order of item ABC only using boxes, but there is still possibility to enter purchase order of 0,1 box (which equals 1 EA). Using this setup MRP will create PO communicate also for boxes .