Previous triggers and event generators have been discussed in post one, post two and post three.
In the previous (#4) post I explained how a task on the same resource object can be triggered after a task has finished with a certain response code. It is also possible to trigger a task on another resource object. This can be done by having the task on the first resource object set a User Defined Field value in the User object. The change of that field would trigger the lookup.usr_trigger explained in post
It should be noted that the definition of the decode name in the lookup table must be exact the name of the task(s) to be triggered.