I need a multi apartment door phone. The set will comprise of one outdoor and multiple indoor (8-10). The outdoor will have numerical buttons each of which will connect directly to one apartment. Like, if I press button1 on the outdoor, it will connect to apartment1 and outdoor will only be able to speak to apartment1 at that time. It should be able to run on battery, preferably rechargeable battery as there is no constant electricity where I want to use it. It may be wired or wireless, either one is ok. But it should be able to connect up to 30 metres across wall barriers. It should be weather proof as the outdoor will be situated on the outside gate. Show More