Clearing Inventory differences from 999 through LI21

Hi Experts,

We are facing a situation here. After LI20, all the difference stocks are lying at 999 storage type. Since the stock at 999 are still available at IM level, these are getting suggested during process order creation. We cannot immediately do LI21 after LI20 since this requires certain approval process. My question to all of you is-- Is there a way to make all stocks lying at 999 as unavailable in IM level as well.

Regards

Roy