string on separate lines match

Here is an interesting case:

I want to file mails addressed to "smartlist" separately, for example:

-----
:0
* ^(To|Cc):.*(S|s)mart(L|l)ist
Smartlist.mail
-----

However with the following mail header, when the string is not in the
same line as "To" and "Cc", the procmail recipe doesn't catch what it
supposed to:

To: Person One <one(_at_)someaddress(_dot_)org>
Cc: Person Two <two(_at_)earth(_dot_)sun(_dot_)com>,
    three(_at_)haha-net(_dot_)org,
    smartlist(_at_)informatik(_dot_)rwth-aachen(_dot_)de

Any suggestions?

Best,
Zhiliang