[exim] expansion variables in routers?

hi -

i'd like to rearchitect my series of delivery routers to be somewhat
more intelligent, potentially through the use of expansion variables.

currently i have a number of "accept" and "redirect" routers that
handle messages based on a number of sql lookups using either in the
"condition" option for the accept router or the "data" option in the
redirect router. in my current configuration, each router does its
own specific sql query to determine whether or not to handle a given
message.

what would be preferable, from an efficiency/flexibility standpoint,
would be to do a single sql query that sets a number of expansion
variables at once. ideally then each router could do tests on these
expansion variables rather than using its own sql query. is this
possible? and if so, could someone illustrate a brief example?

thanks in advance....

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||||||||||| Matthew E. Dunham
||||| Instructional Computing
|||||||||||| UC Santa Barbara
|||||||||||||||| 805 893 7687