Thanks for the tutorial.
Seems to me though that you could skip the whole dependence on Telegram and have Tasker just command the Item directly through the REST API. Since you more than likely already have my openHAB.org setup you can post and put through that address.
Also, you don’t necessarily need to disable the other presence sensors if you use something like Generic Presence Detection to aggregate multiple sensors, though if this approach is reliable enough you wouldn’t need them any more anyway.