It is quite common to create purchase orders for each supplier separately and there is a quick way to do that in Fabrikatör.
1) Go to your Suppliers page
2) Click on "Browse products" for any supplier
3) Select all products since they are already filtered by the supplier
4) Click "Create PO" and adjust the quantities in the way you like. Add or remove line items.
Better than creating POs from scratch right? 🙌