^GroupText();
Displays a small text message to the user if they belong to the specified group. And you can specify an alternate message to those who are not in the group.

Example: ^GroupText("Visitors","You need an account to do anything cool on this site!","We value our registered users!");

Now, that example has a small caveat.  Since the Admin user is in every group, Admin will see that message, too.  To make a message that only Visitor would see, you would do this:

^GroupText("Registered Users","We value our registered users!","You need an account to do anything cool on this site!");

This Macro may be nested inside other Macros if the text returned does not contain commas or quotes.