Help with Getting Help with Google Workspace Transfer

We want to transfer a folder of documents from Google Workspace A to Google Workspace B. Users in Google Workspace A own most of the documents, but not all. Many of the documents have internal links to other documents and we want to preserve those links.

We tried to set up a shared drive in Google Workspace B, but we couldn't copy the files that have owners from outside Google Workspace A. I think we are going to need outside help. Whom should I hire to do this? Thanks.