You can create multiple Purchase Orders across multiple Projects for multiple Vendors at the same time using the Bulk Create feature. You can do this in the Purchase Order Explorer or from the Purchase Orders tab in the Project Explorer.
Click the Bulk Create button:
This will open the Bulk Create Purchase Orders dialog:
To add Projects, click Projects->Add Projects:
On this dialog you can select as many Projects as desired:
The last project you select on the dialog above will be the Project that is initially selected to add items from to the Purchase Orders:
You can change the selected Project via Projects->Select Project:
Use the Add from Project button to choose the items you want to add, either summarized by quantity or listed as units:
You can also choose to add items from your Catalog to order:
The default grouping is by Vendor but you can change this if desired:
All items must be assigned to Vendor before proceeding to the next step or will get the following warning:
You can select multiple unassigned items and click the Change Vendor button:
Each Vendor will be listed on the left side of the dialog and the default is that a new Purchase Order will be created for each Vendor. If that is what you want, click Finish:
However, if there are existing Purchase Orders (with Status = "Draft") for any of the Vendors, you can choose to append these items to an existing Purchase Order:
When you check the "Add to Existing Draft Purchase Order" option you will be prompted to choose an existing Purchase Order for the selected Vendor:
When you click Finish the following prompt will display:
There is a slight difference to the creation of Bulk Purchase Orders when done from the Purchase Orders tab in the Project Explorer. Here you can select the Projects you want to create Purchase Orders for prior to clicking the Bulk Create button: