EXHIBIT 6
                                                                  ---------


                                                          December 20, 2004

Steven G. Felsher
c/o Grey Global Group Inc.
777 Third Avenue
New York, N.Y. 10017


Grey Global Group Inc.
777 Third Avenue
New York, N.Y. 10017
    Attn: Edward H. Meyer



Dear Steve,

We understand that you anticipate exercising Grey Global Group Inc.
("Grey") stock options that you currently own. We also understand that you
intend to use a portion of your existing Grey shares to pay the exercise
price and to satisfy your tax withholding obligations in connection with
the exercise of your Grey options.

In that connection, you agree that, you will exercise, prior to the end of
2004, all of your 2,500 stock options that expire on January 5, 2005. In
that connection, you and Grey agree to treat as compensation income to you
in 2004 an amount equal to the market value of 2,500 shares of Common
Stock, par value $.01 per share, of Grey (the "Common Stock") as of the
date of exercise less the aggregate exercise price of the 2,500 options
($371,250). WPP Group plc ("WPP") agrees that you may pay the aggregate
exercise price of the 2,500 options and the tax withholding obligations
associated with that option exercise by delivering shares of Common Stock
you hold with a market value as of the date of exercise equal to the
aggregate exercise price plus the total amount of your tax withholding
obligations arising in connection with the option exercise. For purposes of
the foregoing, the market value of each share of Common Stock will be
determined as set forth in your option agreement with respect to payment of
the aggregate exercise price, or applicable provisions of the Internal
Revenue Code of 1986, as amended, and the rules and regulations thereunder
with respect to payment of the total amount of tax withholding obligations.

WPP hereby consents to Grey's acquisition from you of shares of Common
Stock as payment of the aggregate exercise price of those 2,500 options and
the tax withholding obligations associated with the exercise of those
options for purposes of Section 5.1(d) of the merger agreement, dated as of
September 11, 2004, as amended, between, WPP, Abbey Merger Corporation and
Grey (the "Merger Agreement"). Except as expressly set forth above, the
Merger Agreement remains in full force and effect.

Please contact me once the exercise of your stock options as described
above has occurred and provide me with a copy of the notice provided to
Grey to exercise your stock options, the number of shares of Common Stock
used to pay the exercise price and your tax withholding obligations in
connection with the option exercise and the amount of compensation income
to you generated in 2004 as a result of the option exercise. My contact
numbers are [intentionally omitted].

If the foregoing reflects our agreement, please countersign this letter and
arrange for this letter to be countersigned on behalf of Grey in the spaces
indicated below.


        Sincerely,

        WPP GROUP PLC

        /s/ Paul Richardson

        Paul Richardson
        Group Finance Director

Agreed and acknowledged as of the date referenced above

By:  /s/ Steven  G. Felsher
   ------------------------------
      Mr. Steven G. Felsher


GREY GLOBAL GROUP INC.

By:  /s/ John Grudzina
   ------------------------------
Name:  John Grudzina
Title: Senior Vice President and General Counsel



cc:  Sir Martin Sorrell
     John Finley
     Kenneth Edgar
     Arthur Fleischer, Jr.
     Laraine Rothenberg
     Phil Richter