Number of Sensors

I am working on a project that will use 6 ping sensors. The GrovePi looks like it has only three analog inputs, which is the type for the ping sensors. Is this correct?

Also would it be possible to change the I2C address of one, allowing two GrovePis to be stacked and be used for my application?

I think that you are talking about the Grove Ultrasonic sensor
You can connect these to analog or digital sensor both and use them directly. This way you can connect upto 10 sensors on one GrovePi. Do not forget to change the pin definitions when initializing the code.

Please let us know how it goes.

Ok, cool, thanks