Child lock

I would like a simple app written that would enable me to disable my children's iphone outside a pre-set time allocation. E.g. I could set the app to allow the iphone to be accessed only between the hours of 8am to 4pm. Else it is locked by passcode. Or could be manually locked or unlocked remotely from my phone. The app would be installed on my phone ( master ) and the childs's phone ( slave ). Each slave could be controlled individually from the master. Locking or unlocking via time stamp or manual override.