Is there a hook for modifying a To: field?

[Chris Green]

I am on a mailing list which has two addresses, occasionally when one
does L[ist reply] the To: address is:-

    ixion at ixiemaster.ixion.org.uk, Ixilist <ixion at ixion.org.uk>

At present I normally notice this and remove one of the addresses but
it would be nice if I could automate this.  Is there a hook (send_hook
maybe) that can be used to change this?  It can't just change every
case of either ixion at ixiemaster.ixion.org.uk or ixion at ixion.org.uk as
most of the time a L[ist reply] only gets a single address.

-- 
Chris Green