In a Business Rule you can use the following. The below is for a task record with a populated wish list. It loops over each user in the watch list and generates an event. Your notification will then look for this event to trigger an outbound email.
In your notification record ${event.parm1} would be the firstName value to use
(function(current, previous) {
//If watch list is empty, do nothing
if (current.watch_list.nil())
return;
//split the glide_list into a usable array
var watchListArr = current.getValue('watch_list').split(',');
//loop over the array, firing an event per user
//watch_list can contain sys_id OR an email address
watchListArr.forEach(function(user) {
//Nicely attempt to find the user by their sys_id
//if 'user' is an email address, we use
//GlideQueries 'orElse' to return the email address
//as the first name value
var firstName = new global.GlideQuery('sys_user')
.get(user, ['first_name'])
.orElse({
'first_name': user
}).first_name;
//fire our custom event
gs.eventQueue(
'my_event', /** event name */
/** the record the notification is for **/ current,
firstName /**Name value to use in the notification */ ,
user /** the sys_id / email address */
);
});
})(current, previous)
