SOLVED Check an object's state across multiple instances

Mr Errorz

I have this object [oBlock], which I have up to 81 instances of it in a room,
it has a few states, and I want to be able to track one of it's states [flagged] and be able to check if none of the instances are currently at this state.
in pseudo code, something like:
if instance_number(oBlock.flagged) == 0
if !instance_exists(oBlock.flagged)

What's a good way to achieve this?