If I send a message to an listserv list, and also to other individual
recepients, like with

To: [log in to unmask], [log in to unmask], [log in to unmask]

then all members on the list only see the mail arriving like

To: [log in to unmask]

while the individuals a and c of course see the full To: list.  This
results in problems as the list members do not get to know the full
recepient list, and also then that any response from them does not reach a
or c.  (Had I wanted this behaviour, I would have used Bcc:)

The full recepient list seem to end up in some 'Comment: To: ...' field in
the mail headers, but this does not help.

Is there an listserv option that causes this behaviour?  My site
administrator tells me that this cannot be changed...

Best regards,
Håkan