You need to create a template to run a perl script.
In the perl script you need to process the output from whatever command you would usually use, and send output back as a message pair. You can have up to 10.
therefore if you have many users then you only want to return ones above a set criteria %?
Then you can create Message Pairs for them and appropriate alerts.
Copy one of the shipped AIX templates and delete the Output Script #n sections from the bottom of the template.
Edit the script, insert your script and assign to a node you want data from, and the new Output Script #n's will be created appropriately..