[Exim] Am i in over my head?

I am wondering if this is at all plausible.

We are using a case tracker (MantisBT) for our customers to log the
usual foray of cases and comments. This is a PHP script which uses the
local SMTP server to send notifications/updates/etc.

Now we would like to be able to send copies of outgoing mail to various
recipients depending on contents of the message body. for instance, the
following pseudo code:

if body contains "Project:                    SMS_T2"
    and body contains "Case ID:                    0000056"
    then deliver to "user@???" and to
"project_manager@???"

of cource the "deliver to as well as the input variables will be mySQL /
pgSQL lookups.

Is this plausible, or am i in over my head here?