If you want 5 LEDs to blink at the same time, connect them in series (with wire between them as required) then run them from the appropriate voltage source with a series resistor.
Assuming they will run at 20mA, there is no need for a thick wire. Simply calculate the required resistance using an assumed resistance of 0 ohms for the wire. Then measure the current and choose a smaller value resistor if the current is significantly low.
You've given so few details that I can't be sure I'm answering your question, but I hope this helps.
oh, blinking mechanism. Use a 555.