When one looks in depth at samples to find a common denominator, sometimes it is necessary to break down products and match snp's with accomplishments and skills. For example in order to trade or use in a burial for ceremonial purposes, objects like clay pottery or copper, one must be able to communicate within a culture, or trade with another culture. Many cultures have their own unique burial practices and objects. Where they can either produce locally manipulated raw materials or acquire grave goods via trade; with a friendly culture. Items like pottery and copper found in, Bell Beaker, Potopovka, Sintashta required skill at producing sufficient manipulated heat, somewhere in the range between 500-1000 celsius.
There are many flavors of different snp's within the Volga region buried in elite style with goods requiring up to 1000C heat. For example there is I0222 khvalynsk; buried with copper ornaments. There is also I0444 buried with a copper cudgel. Related to I0444 there are samples I7670 and I1020, I4253 all related by a string of snp's found in some of the oldest regions with barrow burials in Volga region.
Potapovka I7670 is close to pottery areas like Chekalino and Lebyazhinka-Hunter Gatherer Elshanka style- egg shaped.
Sintashta I1020 is close to the famous Kargaly ore deposits, which explains how his ancestor I0444 was able to acquire copper and use it using heat of around 1000C.

All of the connected samples also have one thing in common; they are largely made up of Eastern Hunter Gatherer and Caucasus Hunter Gatherer components.