Collate list of names(from headers)

Hello All,
New to these forums and I said I would try to help a friend with an excel program but i am stumped.
Help.jpgHelp.jpg
Attached is screencap of my tester sheet, and as you can see the document names are down the first column(Blue) and names are along the top(Red).
The information in black is what permissions people have to each corresponding document. The actual document has over 300 names and many more documents.
My friend wants to have column at the end listing the names of people assigned with each permission as shown in the attachment.
Without having to do this manually which would take a long time is there anyway of looking through B2-H2 for "Lead Reviewer" then finding the corresponding names in A2-H2, then putting these list of names together in I2.
Having looked everywhere on the internet I have found this hard to describe so have been unable to find anything like this.

Any help will be greatly appreciated.

Thanks

Luke