Why don't the Indominus Rex and the T-Rex communicate?

If you watch the previous movies (specifically Jurrasic Park 1993), it's explained that the raptors are able to communicate because they have the need for it in order to hunt as a pack. The T-Rex is a loner and does not communicate; no need.

Additionally, even if the t-rex could communicate, what would they say? "Hey, man, I'm part t-rex too so don't fight me". No, they would both want to be dominant (there is no alpha when there is no pack).

The t-rex doesn't care about being alpha, it cares about being top of the food chain.

Do you remember beginning of Jurassic Park III?

At the start of the film, before Grant attends to the island, Billy creates a model Velociraptor "resonation chamber", a bony structure that enables complex communication.

The Indominus also must have this organ and while it must be bigger in size she is able to communicate with the raptors by using it. We have to assume that the rex doesn't have this organ and is therefore unable to communicate with the raptors or the Indominus.

I think I'm loosing myself here but there is also another interesting paragraph from the article:

Because this sudden chance of appearance of the Raptors violates the continuality of the series, many Jurassic Park fans have tried to create an explanation of this change. In most of these theories, the raptors from the first two movies and the raptors in the third movies are treated as two different genetic versions.

From my point of view this plays out really well after you have seen Jurassic World. Yes these raptors are still this big while they should be smaller and should have feathers according to current research. Indeed these are theme park monsters just as the critics say, in as well as out of universe. While the first film wanted to achieve the most accurate portrayal at the time, the last film — from my point of view — managed to have no major issues being scientifically wrong and also consistent.

Speaking of consistency, did you notice the scars on the rex? We can assume that his is the same rex who fought the raptors in the visitor center at the end of the first film.

Why would she of all seemingly cooperate with the raptors at the end which just switched sides again? "They had fight together against this new threat" sounds a bit silly at first when talking about wild animals as Owen calls them, but we don't know what happened to her during all that time and Blue, the remaining raptor, reallly doesn't pose a threat to her.

All we know is that there is a variety of not only different species but probably also differently engineered individuals or individual production batches and that some of them can adapt very well.

Also for critics to consider, assets/lifeforms from previous movies didn't just became obsolete and died the moment contradicting research was published.