we have 30 cameras located on 3 different sites

there are 3 seprate locations with 10 cameras on each site

now my task is to connect all these cameras in such a way that i can monitor any one of the cameras at any time i want to.

the options i am thinking about are

1/ putting a pc at each of the 3 dvrs with a 3 g card so that i can log into the pc from another pc in my office and monitor staff working on the various sites.

2/ put a pc like mentioned above but have a smart cellphone which i can log into the cameras from the cellphone and monitor staff.

the cameras are all fitted with motion sensors and they are day/night rated...

so if there is a breakin on one of the site... when the camera switches on to record it must activate on my phone or laptop so i can see whether it is a breakin or whether a dog or ghost is running around on site.

any ideas?