[exim] No-op router?

Hi all
I'm using a virtual users setup with a mysql database.
I'm trying to reduce the number of sql lookups because there are just
too many simple queries at the moment (is forwarding enabled,
store-and-forward, vacation,...).
Now I want to have a router whose sole purpose is to fill address_data.
On subsequent routers it would then be possible to use
${extract{var}{$address_data}} instead of all these lookups.
I don't want to set this on a "real" router because they all only apply
if some conditions are met.

Is there a way to have a router only add address_data and pass the
message on to the next router?

(I tried using a verify_only router with an acl that set a custom acl_c
var with the content of $address_data. This almost worked - I got stuck
with a redirect router, as the "new" forwarded mail had the same acl_c_
vars, but needed to have its own).

Thanks, David