Your assumption is correct, and the location that you specified is where an Administrator can add Bob to John's mailbox permission list. Or John give Bob permission himself in Outlook by right-clicking on his mailbox (in the Folder List) / Properties / Permissions Tab
Then on Bob's login, you can add John's mailbox to Bob's profile as an ADDITIONAL mailbox, or you can create a separate Outlook profile to access John's mailbox.
ADDITIONAL:
Under Bob's login, Control Panel / Mail / Services Tab / select Microsoft Exchange Server / Properties / Advanced / Add... / put in John's name or exchange alias / OK / OK / OK
This will ADD John's mailbox to Bob's profile. In Outlook, Bob will be able to expand and navigate through John's exchange mailbox and his own simultaneously. Enabling the Folder list (View / Folder List checked) is the easiest view in my opinion.
SEPARATE:
Under Bob's login, Control Panel / Mail / Services Tab / Show Profiles / Add... / Then run through the wizard to set up the new profile for John's mailbox.
In Outlook, change the options so that Outlook prompts for which profile to use while starting up. Tools / Options / Mail Services tab / Prompt for Profile to be Used / OK
Outlook will now prompt for which profile to open when starting. For Bob to access John's mailbox, he must exit Outlook and restart Outlook, selecting John's profile, and then exit and start Outlook again to switch back to his own mailbox.
--C
