Not sure about stopping a timer once started, but I have a process with a timer loop that controls the periodic execution of a piece of logic, however the time between executions may vary. So my trigger fires more frequently than it may need to, and triggers a service task that performs further checks to determine if it is the right time. If it isn't it triggers the re-setting of the timer, otherwise it proceeds to the periodic execution.
Dependent on your use-case, maybe you could use this approach and check if a delay or suspension of the trigger has occured before proceeding.
