Blacklist yahoo group problem?

[Carl Boberg]

Hi,
I need to blacklist a yahoo group which uses the below form as from address:

sentto-10798619-42-1097426196-[name].[lastname]=nrm.se at returns.groups.yahoo.com

the stuff in [] is edited by me to not disclose the user
The numbers in the from address change from email to email.

I do not wish to blacklist returns.groups.yahoo.com so how can I go about blacklisting this spamming yahoo group...?
It goes by the name [International_Real_Estate_Auction_136] or 137... 

Any ideas?

Cheers
--------------------------------
Carl Boberg
System & Network Administrator
Swedish Museum of Naturalhistory
Frescativägen 40
104 05 Stockholm
Sweden
Tel nr: 08-5195 5116
Mobile: 0701-82 4055
E-mail: carl.boberg at nrm.se
--------------------------------  
 

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