I'm not entirely sure what you're asking, but I will say that 1 pump/group is a very rare and relatively new thing in espresso machines. 1 pump per machine, regardless of the number of groups, is typical, indeed virtually ubiquitous. The Hydra was the first machine I heard of doing this, and it seems that La Marzocco has followed suit with the Strada and with adding the option to their other machines as BTO. I don't know of anyone else doing the same thing.
It's also not strictly required for pressure profiling. I believe the Slayer has only one pump, but uses needle valves and bypasses and the like to achieve pressure profiling on each independent group.