How to group contours in close proximity to each other?

Hi all, first time on here.

As per the attached diagram, I’m trying to use openCV commands to group together all proximal blobs in an image, box them with a minimal rectangle and return size of the largest group of blobs (minimal rectangle) and the coordinates of its X and Y position on the screen. Origin is at top left. Ideally, it would also return order of size; largest to smallest, of all blob groups and their respective X and Y centroid coordinates.

Any assistance much appreciated.