general database password

Hello,

I have maybe a strange question:
Is it possible to configure a main password for a hole?

For a better understand:
Only my program knows this mainpassword and if my program can connect
and is connected, the user can connect to database (with his own
account). The user is only allowed to connect, if he is connecting with
my program.
The problem is, I can't say, that users only from a special hosts
(pg_hba.conf) can connect, because I do not know from which host the
come.

If something like that is possible, please let me know how, of not, than
it is also ok.

Thank you

Daniel