Document flow from EDI Sales Order

Hello SAP community

I would like to ask you how can I link Sales Quote with Sales order which has been created through the EDI.

the process is: We are creating Sales Quote manually --> then we are creating appointment (Measure) by follow up activity --> then customer is uploading Sales order through the EDI --> we are creating appointment (installation) by follow up activity from SO.

As you know we are missing connection between SQ+appointment and SO+appointment. Right now we have 2 document flows and we would like to have only one. Is there any possibility how to do it?

Thank you in advance

Filip