Using Odoo 13 CE.

I have a dual company setup wherein i sell the same product in 2 different companies & generally they both have their own locations.

Due to prevailing situation, I am forced to sell it through only  company A even though i need to take orders & purchases from company B, how do i set up the product in company B so that the purchased stock is directed to company A & both companies sell it from the same inventory? The product is of storable type. & there is no company defined in the product, still it shows as a different product in both companies.