Adding manually uploaded attachment in Email Bursting

Summary:

Is there a feasibility to attach manually upload files in Email Bursting along with Bursting output

Content (please ensure you mask any confidential information):

We have created an Email Bursting for the Project Invoices when there is a change in the status of the Project Invoice Email will be communicated along with the Preview Invoice Template as attachment.
Now the Business requirement is to send the Manually uploade File while Approving the Invoice through Workflow.
I tried multiple ways to send the Manually uploaded document through BIP Bursting feature.

Is this feasible to attach the manually uploaded file along with the Bursting output. Please suggest or provide any workaround on this.