I want to create a PCB board that would have:

 * input - 5V wall outlet USB charger or for example MeanWell Din power supply 
 * output - 3 usb ports that would be used by RPI-like devices. (5V 2A max each).

Question - since all devices would share same power line and I can expect noise from the consumers - could you please point at extra circuit items that I should use ? 

I would imagine that it should contain capacitors from 5V to ground near each output and probably optional input capacitor (not sure if needed with quality power supply's).

And I would also assume that RPI-like devices have already some input filtering in place, so probably it would be overkill.

Also, there would be no data lines included, just the power lines.