BMW 2002 Alpina vs. Ford Escort BDA - Zolder 1972

Four Escorts fighting against an Armada of BMW 2002 / 1602. Two of the Escorts are Zakspeed-Cars, other two I can't identify. One of them might be BP-Belgium.
All well-known BMW-Tuners are in this race: Alpina, Schnitzer, Koepchen and the yellow-black GS-Vergölst-Car is also there.
Having a closer look you can spot a single Opel Manta, an Opel Ascona and a dark blue / white striped Kadett B (probably Otto Kälberer) is passing one of the slower Escorts.
There's some other cars to be seen in the paddock, including a bunch of Alfa GTA. Really don't know, why the Alfas are not in this most likely 2-litre-class-race.
This is probably a race in Zolder in 1972, but I don't know for sure.