You already asked this same question regarding Paroon Sharks, and already received the perfect answer from
Fishman Dave
in that thread. The same answer is true here, and is in fact true for almost any large fish. There are any number of fish that can live with a Fill-In-The-Blank monster fish, if you are careful regarding relative sizes. Many many predators are not aggressive and won't bother a fish too large to eat.
But if you just want to throw two different mega-predators together willy-nilly and expect them to live and grow indefinitely and maintain the same growth rate and the same relative sizes, so that one never outgrows the other, then the simple answer is probably No. The odds are that eventually the faster-growing fish willl outstrip the slower one, and eat it. When one of the fish is an extremely fast grower, like the RTC, then that day will come sooner rather than later.
Thinking about and being aware of compatibility doesn't somehow become unnecessary after you buy the fish. You actually have to keep an eye on them throughout their lives, and expect to make adjustments as they age and grow.