That is highly unlikely to be a good idea!
A Fastrack - or any such GSM Modem, for that matter, is really not well-suited for a “Server” application!
Don’t use modems!
Use a proper “Bulk SMS” service!
See:
viewtopic.php?f=53&t=3729&p=14804&hilit=bulk+sms#p14804
viewtopic.php?f=41&t=3643&p=14049&hilit=bulk+sms#p14049
viewtopic.php?f=53&t=3281&p=12295&hilit=bulk+sms#p12295
viewtopic.php?f=53&t=3237&p=12102&hilit=bulk+sms#p12102