rejecting local users with fake envelope sender

[D. Karapiperis]

Hello all

I am trying to configure properly reject_unlisted_sender ,which utilises 
all possible sources of valid mailboxes or mailaliases,
so that local users (originating from my_networks) can send mails using 
valid envelope sender ( or even both sender and the from field)

Is this possible?

Thanks in advance
Dimitrios