[exim] is this possible with exim

I want to set up a router that will do the following. I wanna send and email to a specific address say

list@???

then have the list@??? expanded to a set of email addressess. The router will then pass the exapnded $local_part of each email address to a pipe transport which then would parse it to a script for further action.

Can anyone point me in the right direction?
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