Need a Formula to Check an Audit Log Against a List of Groups of People

Hi,

I have a SharePoint document library on which I run an audit log report to see who has opened each document. It generates a workbook that contains data like the example below. I'm trying to shoehorn this data into a format that the boss can use as a required-open report. The data looks like -

Group1, Person1, Person2, Group2, Person3, Person4

Filename, Read by,
File1, Person1,
File1, Person2,
File2, Person1,
File3, Person3,

I have a dynamic list of people in groups required to open a specific subset of the documents. I've written a macro so that I can pull the group names and membership into cells in the workbook. Is it possible to write a formula that transforms the data into something like this?

File1, Needs to be read by no one in Group1, Needs to be read by Person2 and Person4 in Group2,
File2, Needs to be read by Person2 in Group2, Needs to be read by Person3 and Person4 in Group2,

and so on?

Does that make sense? I'm uploading a sample file if that helps. This isn't something I'd normally do in Excel but that seems to be all I can export from SharePoint. Thank you very very much for any help!!

Josh