Agreed - yes it is too bad. But I'm not giving up my four group without a struggle
He's now looking at having a small on-demand point-of-presence hot water system adjacent to the machine with a small faucet and drain. His intended use if rinsing portafilters but IMO his volume will be such that he could just balance use of the left and right boiler and rinse them with water form the brew groups. if usage is balance correctly.
Perhaps even better would be to add a preheat for the brew boiler and PID the darn thing but I think that's more than he's up for at the moment.