Could you please advise on the possibility to change the status of a server using a job/task ?

I have n tiers applications on which I have VisualCron servers on all tiers. I have sometimes to restart the tiers, the applications, or simply switch the application off. I do not want the jobs to be triggered when all tiers are not available.
Using a thrid VisualCron server, piloting the visualcron servers on my tiers, could solve this.

I can not stop the visualcron service, as I do not want the services (and jobs) restart when the tier reboot.
I can not use the time exceptions, as I want to be able to launch the restart manually at any time.

Thank you,