[exim] Router with two transport and condition

Hi, list!

Is it possible to define TWO transport (of the same type!) for a router, and
a condition in the transport?

I have two transports: one to send E-Mail to external servers, and another to
do the same, but with DomainKey-signature.

Right now, I have two routers, too. The first use the first transport and the
second the second one.

I'd like to have just ONE Router for external servers, and the right tranport
to be used, if the sender domain has the Keys or not.

Is it possible?

Thanks
Luca Bertoncello
(lucabert@???)