rewriting depending on routing

Dear all,

I'd like to use the address rewriting rules only on specific cases,
linked to the router decisions.

Is this possible ?


--more details--
To allow our central mail server to proceed an outgoing message,
its headers and envelope fields must be rewritten.
This is done with a rewritting rule and a domain-list router.
And I am very satisfied.

To send a message inside our domain, I set up another
domain-list router. This works, ... but in this case too,
the addresses are rewritten, and I'd like to avoid that.
-----------------

Thanks for any remark / hint.

Bruno Vuillemin, Universite de Fribourg {Suisse/Schweiz/Switzerland}