asterisk users - Apr 2006 - Any way to prevent this from happening

Typical user error, one user forwards his calls to another using CFwdAll on
Cisco 7940, but the user receiving the call has done the reverse.

    -- Called 117
    -- Got SIP response 302 "Moved Temporarily" back from 10.139.2.15
    -- Now forwarding Local/117@sip-0eb7,2 to 'Local/114@sip' (thanks to
SIP/117-df17)
    -- Executing Macro("Local/114@sip-35cf,2", "stdexten")
in new stack
    -- Executing Set("Local/114@sip-35cf,2",
"LANGUAGE()=en") in new stack
    -- Executing SetMusicOnHold("Local/114@sip-35cf,2",
"aviareps") in new
stack
    -- Executing Dial("Local/114@sip-35cf,2",
"SIP/114|20|t") in new stack
    -- Called 114
    -- Got SIP response 302 "Moved Temporarily" back from 10.139.2.14
    -- Now forwarding Local/114@sip-35cf,2 to 'Local/117@sip' (thanks to
SIP/114-2036)
    -- Executing Macro("Local/117@sip-a3a3,2", "stdexten")
in new stack
    -- Executing Set("Local/117@sip-a3a3,2",
"LANGUAGE()=en") in new stack
    -- Executing SetMusicOnHold("Local/117@sip-a3a3,2",
"aviareps") in new
stack
    -- Executing Dial("Local/117@sip-a3a3,2",
"SIP/117|20|t") in new stack
    -- Called 117
    -- Got SIP response 302 "Moved Temporarily" back from 10.139.2.15
    -- Now forwarding Local/117@sip-a3a3,2 to 'Local/114@sip' (thanks to
SIP/117-3adf)
    -- Executing Macro("Local/114@sip-15b7,2", "stdexten")
in new stack
    -- Executing Set("Local/114@sip-15b7,2",
"LANGUAGE()=en") in new stack
    -- Executing SetMusicOnHold("Local/114@sip-15b7,2",
"aviareps") in new
stack
    -- Executing Dial("Local/114@sip-15b7,2",
"SIP/114|20|t") in new stack
    -- Called 114
    -- Got SIP response 302 "Moved Temporarily" back from 10.139.2.14
    -- Now forwarding Local/114@sip-15b7,2 to 'Local/117@sip' (thanks to
SIP/114-e4df)
    -- Executing Macro("Local/117@sip-fe51,2", "stdexten")
in new stack
    -- Executing Set("Local/117@sip-fe51,2",
"LANGUAGE()=en") in new stack
    -- Executing SetMusicOnHold("Local/117@sip-fe51,2",
"aviareps") in new
stack
    -- Executing Dial("Local/117@sip-fe51,2",
"SIP/117|20|t") in new stack
    -- Called 117
    -- Got SIP response 302 "Moved Temporarily" back from 10.139.2.15
    -- Now forwarding Local/117@sip-fe51,2 to 'Local/114@sip' (thanks to
SIP/117-5ff1)
    -- Executing Macro("Local/114@sip-2164,2", "stdexten")
in new stack
    -- Executing Set("Local/114@sip-2164,2",
"LANGUAGE()=en") in new stack
    -- Executing SetMusicOnHold("Local/114@sip-2164,2",
"aviareps") in new
stack
    -- Executing Dial("Local/114@sip-2164,2",
"SIP/114|20|t") in new stack
    -- Called 114
    -- Got SIP response 302 "Moved Temporarily" back from 10.139.2.14
    -- Now forwarding Local/114@sip-2164,2 to 'Local/117@sip' (thanks to
SIP/114-45e0)
    -- Executing Macro("Local/117@sip-ec18,2", "stdexten")
in new stack
    -- Executing Set("Local/117@sip-ec18,2",
"LANGUAGE()=en") in new stack
    -- Executing SetMusicOnHold("Local/117@sip-ec18,2",
"aviareps") in new
stack
    -- Executing Dial("Local/117@sip-ec18,2",
"SIP/117|20|t") in new stack
    -- Called 117

Does anyone know of a way to prevent this from happening by dialplan
manipulation? Also, same thing happens when a user forwards all to him or
herself.

Regards toall,
Joe