On the surface, your question appears to me to be a type of "cluster analysis" (https://en.wikipedia.org/wiki/Cluster_analysis ). I know very little about these algorithms, but have encountered them before. This thread should have a good introduction to these in Excel: https://www.excelforum.com/excel-gen...of-values.html This thread had quite a bit of discussion, several links to outside sources, and some examples that could be of value. I doubt you will find a turnkey solution in that discussion, but it should provide a good start towards your own solution.

From what I can gather, cluster analysis can be somewhat simple or can get quite involved depending on the details of a given project. It will probably be important to carefully define exactly how you intend to identify "congestion" or "clusters" before getting too far into the programming aspects.