No, the Pi4 and Pi2/3 series are just using the "USB" style connector to deliver 2-wire power. They do not emulate a USB device on the power port. That is why some people had issues with Pi4's and "smart" USB "C" chargers that would refuse to power the Pi. The smart chargers expected the device to negotiate their charging current and the Pi4 couldn't do that.
You'd need to fuse each leg off a common supply for safest use.
