[Exim] Splitting query results for partial processing

Hi,

I am using a LDAP query to get data from my LDAP database. The query
returns one (of more) results, which Exim uses to redirect the incoming
message. For example:

test@???
-> redirected@???
-> |/bin/myscript

LDAP returns this as:

redirected@???, |/bin/myscript

I would like to do some extra processing on the e-mailaddresses that are
returned. One of the reasons is to allow spamboxes. If the envelope
address contains '+spam' (test+spam@???), the resulting alias
should also contain '+spam' (redirected+spam@???).

Is there a way to split the result of the query and do some extra
processing on the address-type results?

redirected@??? -> add +spam if needed
|/bin/myscrypt -> no address, just pass it through
/dev/null -> no address, just pass it through

Is this possible with Exim's string expansions? Or will it need some
external scripting?

Sincerely,

Eric Bus