Bill of Materials Purchase orders

Hi, i was create a virtual products in new product (BOM), and i can’t to find how i can to create “Purchase orders” according this virtual products, i was create a Project for this BOM but there i need manually insert all products of this BOM, anyway my list of products in virtual product have items from several vendors…
I can’t believe the dolibarr haven’t option to manage and create Purchase orders from virtual products list.