This is another great free application from Shubaroo.com that allows you to send one SMS to several recipients in a very easy fashion.
In fact the integration with Outlook Mobile is brilliant, and all you have to do is set the Category property in the contact.
Once you do this, you can choose from the different categories the ones you wish to receive the SMS. You can even unselect people inside that category.
To download this software please visit Shubaroo.com