Hi Gedmo
Welcome to the forum
An interesting concept but, how could it be handy if you are in the UK or even in town at the supermarket and are alerted to intruders in your property in spain. I can't see any key holder going in to confront intruders.
There are also many companies in the area providing such services already, including 24/12 monitoring, so perhaps you should have another string to your bow. Starting a business in Spain is not easy.
I would be interested to hear from any of our many members if they have experience of this sort of secutity system.
I don't want to sound negative, just practical
Anyway good luck
John