A client has a need for about 2500 dependencies. One for each remote site. Using the regular method of creating groups will not work, since the groups are limited. So I decided to use custom properties. Why not - we use custom properties for just about everything else.
2) Set custom properties on nodes by what ever means (edit node, group edit, export then import)
3) Set up the alert using SQL condition
4) Write a report to verify custom property dependency settings
I have tested it out and the alerts are working and picking up the dependency information.