Looking at the MIME::Lite documentation, it seems you can pass an array reference to the add() method. Otherwise, you might follow the doc example for the Cc field:

my $msg = MIME::Lite->new(
    From => 'someaddr@here.com',
    To => join(',', @$addrs),
    Subject => 'Subject Text',
    Type => 'TEXT',
    Data => $$Lusertxt,
);
[download]

Your mileage may vary. I don't have it installed, and I'm super lazy, but at least you got a response. :)