Rewrite "Return Path" or other host information?

[Edward Tsang]

Hi there,

How can I completely rewrite "ReturnPath" or "Host information" in message
header in qmail?

For example,

A mail ---> relay to B's qmail ---> C final destination --> receiver.

I want the receiver or other user will return mail to B instead of A.

Currently, if C's receiver return mail, it will try to contact A server.
However, there are no sendmail/qmail daemon in A.

Regards,
Edward.