Weighing Point Clusters

Hello !!!)
I wanted to ask your help it creating a unified formula for weighing certain point clusters. I have a list of points where each has a weigh attributed to it. I have a cluster dimension parameter which defines how many points will be in one cluster. I am able to find the number of points belonging to one cluster but I need to extend this further to perform calculation NOT on the points belonging to the cluster but –indirectly – on the WEIGHTS which belong to all the points in the cluster. At first I need to AVERAGE the weights belonging to the points in the cluster. I need a formula approach to this question as I am going to tweak it extensively in the future for all kinds of indirect array calculations. Please see the attached workbook which shows in detail how the calculations should be made using one of the clusters – lying around the 21 point as an example.
Thank you very much for your time!)
Dima