PO creation for the requisition of OSP

Morning Experts!!!

We have a standard Depot Repair, WIP and PO modules implemented. Below is scenario and I need your help getting more inputs on specific issue I have.

We create a SR, under which we have multiple Repair Orders created, each for different activity (per business requirement). We create a WIP job against each Repair Order and most of the time, we have OSP requirement so we end up creating a requisition per WIP job (so per Repair Order). 

I understand that we can use Autocreate form, select multiple requisition line(s) and then create a single PO. Do we have any functionality that enables us to create a single PO for all requisition which comes under the other Service Request. If not, is there any way we can automate the PO creation process. We are open to have any option like Standard PO or even Blanket releases, etc.