What do I need?

A DMX Controller maybe your best bet. You can still set up in master/slave mode when needed. Welcome to the forums.
Sincerely,

My idea is a bit impractical, but hear me out.

I am assuming you're doing this all within an event. It looks sloppy to reprogram your fixtures during an event. I'm sure your guests won't give a crap, and that's fine since that's all that matters anyways.

My suggestion involves doing something that you're normally not supposed to do.

I am suggestion a second pair of the units. Put one pair with DMX, use with the controller. Use another pair as master/slave, and then turn them on/off via a relay/switching pack. You shouldn't run these off a switching pack because you can damage them or at least the chance of damaging the lights is greater than average. Using a switching pack tends to help. Even so, it's still not recommended, but it COULD be done.

I think you'd be best off having a DMX controller of some sort and then an UC3 for the other pair.

So, you want to eliminate the cheese but keep the look. OK, not bad.

If it was me, I'd find a safe way to switch pairs safely, even if it meant having a power unit with remote turn on/off, which is most likely how I'd want to go. But I ain't going there yet.

Thanks for the advice fellas

Jingles, if I use a DMX Controller would I program a single show with them then slow the speed and change the color manually. Or would it have to be two different shows (one for fast songs & one for slow) and just switch back and forth? I have other Dance Lighting so a minute or two of transition time wouldn't be a problem.

Depends on which controller you are using. Let me know.
Sincerely,

True. Say, you're using a DMX Operator, there is a fader to control the "scene change speed" so no need to program different shows if that's how you want to go about it.

Sweet DMX Operator it is then...Thanks Again!

I really like my DMX Operator, so I recommend it a lot. I also like MyDMX.

Have fun programming your scenes for your DMX Operator. It takes a little practice but you should get the hang of it quickly. what I d recommend is that you keep a set of handy cheat sheets with names for your various scenes, notating which banks they are in as well. While you may only have so many chase sequences(6 I think), using scenes you can get around that a bit.

Enjoy. The DMX Operator is easy to use and has a lot of capability. And since it has that fade time adjust, that should save you quite a bit as well.