Put cap of Planned order on items once PLO size for entire category reaches 2700

Summary:

There is a category having 6 items. All the items in this category are purchased from same supplier. Requirement is to put a cap of 27000 units per month on supply orders created for all items in this category. There is no proportion for individual items however once the order limit reaches 27000, there should be no more planned orders. If the order size exceeds 27000, elimination should be same proportion basis.

We discussed defining supplier capacity but it will not stop planned orders creation only highlight overload.

Then also thought of a planning BOM or phantom BOm grouping all these items. 

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