Make a copy and data gets added to the master

In essence, this is what is achieved with the help of data stored on a Cloud, where various copies are kept in synch with the master. GIThub works on this principle. I use Mozy Synch for that purpose (now Carbonite) and there are lots of similar systems around "shared" files on local networks. Individual systems allow users to determine which copies are allowed to update the master. In fact, GIThub is a decentralised system which has more than one master.

All of this is controlled by programs that kick in based on events and circumstances. If you want your own Master updated when data are added or modified on a copy you will need your own program to do that for you. Such a program would have to have access to both your Master and the Copy. You will find this latter requirement a useful consideration when you think of how to realise your ambition.