How to set access for Sales Support role

We have a dealer instance with the following reporting structure - Sales Person, reports to Dealer Manager, reports to Dealer Executive.  We would like to set up a role for "sales support" - new role, with access to only those opportunities for a sales team/Dealer manager.  E.g.  John Smith, Dealer Manager has 5 direct reports, new role would report to John Smith directly as well, and would like to have access to ALL OPPY's for John's sales team/direct reports.  Is this possible?  If so how do we manage access for this role, limiiting it to ALL OPPY's for a single Manager.  Thanks!