all directly to the same and only point.

Aha, and where is this POINT? If you have a look into a PC, is this point where the USB connectors sit? Or, where the SUB-D printer connector sits? Or where you connect the monitor? Or, where the protection earth connector of mains cable is connected to?

This 'all directly to the same and only point' does not work with high speed applications. Then you need to follow the concept of 'radio frequency plane' or 'chassis plane'. And all internal grounds must have a connection to this chassis plane, not at only ONE point, but at as many points as possible. Have a look into any PC!

Kai