GREY GLOBAL GROUP INC., WPP GROUP PLC, WPP 2005 LIMITED, WPP PLC, WPP AIR 1 LIMITED, WPP AIR 3 LIMITED and AMERICAN STOCK TRANSFER & TRUST COMPANY, LLC, as Trustee FIFTH SUPPLEMENTAL INDENTURE Dated as of October 7, 2008 To the Indenture dated as of...