scan aliased emails

Hiya!

I was wondering if there is a way to change the directors in exim so that email aliases to non-local domains are also spam scanned?

Let me explain. On some of our servers, alot of our clients are aliasing their emails to their home ISP email. This ISP has implemented a heavy handed ip based auto blocking spam solution. So all emails being sent from these particular servers to this ISP, are being blocked by IP.

I'm guessing exim is set to not spamcheck emails that are forwarded/aliased off to non-local domains?

I'm also guessing this is the right director to change? Im just not sure how.

virtual_aliases:
driver = redirect
allow_defer
allow_fail
data = ${if exists{/etc/virtual/$domain/aliases}{${lookup{$local_part}lsearch*{/etc/virtual/$domain/aliases}}}}
file_transport = address_file
group = mail
pipe_transport = virtual_address_pipe
retry_use_local_part
#include_domain = true

OR

virtual_aliases_nostar:
driver = redirect
allow_defer
allow_fail
data = ${if exists{/etc/virtual/${domain}/aliases}{${lookup{$local_part}lsearch{/etc/virtual/${domain}/aliases}}}}
file_transport = address_file
group = mail
pipe_transport = virtual_address_pipe
retry_use_local_part
unseen
#include_domain = true