Oracle Database Discussions

I need to run a script when a certain groups of users logon.

I thought that if assigned said users a profile then i could create a logon trigger to check for that profile,
and if the user loging on is a member of the given profile run an extra sql command/script. otherwise do nothing.

but i cant workout how to do that. and google hasn't been much help.

does anyone have any idea how i might do this ?
or suggestions of other ways to run a script/command when someone is a certain "group" logons to a database ?

thanks,
Malcolm.