Even before this form of group painting emerged, there were cases where two artists would work on the same large canvas. An example is "The Taking of Sevastopol" painted 1944-1947 by Pavel Sokolov-Skalya and Andrei Plotnov. I viewed it when I was in Málaga, Spain in November where I visited a branch of Saint Petersburg's excellent Russian Museum. It was holding a year-long (ending February 2019) exhibit titled "The Radiant Future: Socialist Realism in Art." A fine exhibit. Plenty of paintings, some of which I even knew about before I visited. Of course I took lots of snapshots, including some of The Taking of Sevastopol, shown below. Click on images to enlarge.
The term"tag-team" in the title of this post has to do with a feature of American professional wrestling whereby two two-man teams participate. Only two opponents are in the ring at one time, but team members can be substituted if the man in the ring touches (tags) his teammate waiting outside the ropes.