Raspberry connected to adhoc and wifi simultaneously
The best architecture is to use your master 'Pi as a WiFi router.
There are many software options for this ...here is one.
Avoid the use of Ad-Hoc networking if you can. 

The advantage here is that you can implement at least basic security and provide dynamic IP addresses (you don't want to manage fixed IP addresses if you can avoid it) to all your camera 'Pi's.

Your master 'Pi can then pre-process and forward your data to the Internet via whatever networks you have.

You can plug two WiFi adapters into your master 'Pi to enable it to connect as a client to other WiFi networks. Note however that most WiFi stacks will not allow you to connect to two SSID's simultaneously. It is possible to promiscuously connect to multiple networks, but this is somewhat complex in implementation, so I'd advise against it.