Wiring stripboard tracks to common ground
It's straightforward to use the required series resistors to wire the output pins of an ATMEGA like http://www.arduino.cc/en/Hacking/PinMapping to the anodes of 8 5mmx2mm rectangular leds like http://www.rapidonline.com/Electronic-Components/Kingbright-L-383IDT-5x2-5mm-H-i-Red-LED-Rectangular-56-0398 packed side by side onto 0.1 inch stripboard.
However, I'm facing a puzzle when trying to wire the LEDs' cathodes together to ground. It's fairly easy for me myself to do this, just by free-soldering a couple of spare legs directly over the cathode tracks, or chaining loads of wires. However, I can't see myself guiding 45 people through this in a workshop without hassle and errors.
Does anyone have a simple way to wire 8 'odd' stripboard tracks together to a ground track (the 'even' tracks have the anodes in them).
To give a flavour of the solutions I'm considering, I'm looking into 0Ohm bussed resistor networks like http://www.interfacebus.com/resistor-network-schematic-bused-resistors-sip.html to wire theparallel tracks into a single ground track using a standard through-hole component with legs clipped off. However I'm having trouble sourcing anything like this, and I'm sure others have better ideas.