Insert extra type alert

[Phoenix-Blue]

Hi,

Question, I’m no prof programmer so I hope somebody can help me with the next question.
I need an extra type of alert basically an kind of second SMS type in place of the current URL so you can choose 
email/SMS1/SMS2

I use the URL string not any more so I hope it’s possible to insert on some way an extra SMS-Gateway like this.

define('BO_SMS_GATEWAY_URL1', 'http://URL1');
define('BO_SMS_GATEWAY_URL2', 'http://URL2');