How to add Stock Dimension


I want to add stock dimension / level to the inventory for suppliers, means i want to manage inventory by suppliers also,
i’ll purchase items from suppliers and while selling or transferring i’ll select the suppler too,
so the output should tell the balance , in, out, valuation etc according to the supplier.
now erpnext uses three levels for this, company, item and warehouse,
how can achieve to add 4th level same like this, or i’ve to create warehouse for each supplier?