Hi there!

It's not a myth. Logic can indeed network two computers together to combine power. It's called Nodes.

Here's a good link for you:
Networking Macs: Using Nodes In Logic

I've never done it myself but I have a colleague who writes soundtracks for some pretty high profile video games and he nodes two Mac pros together for his stuff.

Another option would be to daisy chain multiple iMacs or or Mac Minis together via the thunderbolt port.