Multiple Mining Turtle Control

Hey guys, I've been trying to figure out something while using Turtles and I can't find a solution. Is there any way to enter a single command into multiple Mining Turtles at once? I want to enter "excavate 1" into 4 Mining Turtles at once so they go down a shaft and stop at bedrock, like a one-way lift. If you know if this is possible or know how to do it, please tell me! I'm desperate to know! (BTW, I use ComputerCraft as part of the Technic Pack but I thought it would be easier to get answered here on the official ComputerCraft forums.)
-Cheers, Sgarr17

Try using wireless mining turtles and a computer with a modem attached, and use the Rednet API, specifically rednet.broadcast( String )

can you walk me through how to do that?