1. Set grid to view 1000 per page

2. Select the Supplier from the 2nd filter on the page

3. Use Multi Item Actions --> Select All on Current Page

4. Use Multi Item Actions --> Force OOS

5. Then use Multi Item Actions --> Force Update Selected

6. If you have more than 1000 items from the Supplier, then move on to page 2 and repeat steps 3-5 and so on.