Well, there are easier ways to group lights. One way is to put them onto a gang of figure buttons, when using a DMX controller. If you have the channels, it's a good way to go. If you're short on channels or fixture buttons, you can duplicate addresses, nothing wrong with that either.
If you're using software controller and that 3D Visualizer is really critical to your lighting design, then yeah, do that other grouping method in the software, which is really the best way to go in a software package.
I'm in the proces of designing my addressing scheme to work with both my DMX Operator and MyDMX. Thanks to MyDMX, it's going well. If you properly plan your addressing, you can get a lot done without having to redo your addressing when you go back and forth.
I would guess you've got enough channels and fixture buttons left over on your DMX Operator Pro to get the job done. Just concede a litle bit and assign all your 64B LED Pros to the same address and then they'll all be on one fixture button. Simple and easy control. I think once you get into programming your controller, you'll see what you can really do.