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Hello Lynn,

Generally a document management software (DMS) would have this capability and there are several with API integrations with Sage 50 US. 

I provide a software called Content Central.

Most Document Management software solutions can be utilized Enterprise wide so it is not limited to only Accounting related functionality. I would first ask your IT department if a similar system is in use in a different department so you can piggy back and configure for your needs. 

Based on your provided needs, a Document Management software could allow you to scan paper invoices or upload electronically received invoices directly from within your email system. The invoice would be tagged with a project/job number (additional Metadata could be pulled from Sage for validation) and could be automatically routed to the correct project manager within the software for review and approval. Project managers could have limited access to only see the project documents that pertain to their needs.