Hello,
What you are looking to achieve is very much possible and for you I would suggest our Elite line of NVR's and IP cameras and you can have the two NVR's recording simultaneously on a local private network and as an additional back up feature I would suggest for a couple or a few of the cameras to have a built in microSD card slot which would provide another back up measure should anything ever happen to the recorders themselves you would always have some back up footage on the sd card.
I would be happy to further discuss the set up with you please call toll free 866-573-8878 extension 127 when you have time.
Thanks,
Eric Wilson