Zend certified PHP/Magento developer

Make sub-network accessible via a static ip of another network

Please forgive the nature of this question but I cannot figure out an efficient way to archive the following:

Someone is opening a store within a mall for example. This store has its own closed network with several network devices like ip cameras, a pos system, digital signage, etc. The stores network is connected to the internet via the malls internet connection, all stores are in fact. Since the mall only has one incoming internet connection from their provider, there also is only one static ip address for the whole mall, right?

My question is, what if one of the stores network components – the pos system for example – needs its own dedicated static ip address to communicate with a server for example. How can this be archieved since the mall provides the internet access for the stores? How can you statically access specific devices within another network with only one ip adress?