Spinosaurus VS Indominus Rex [Who Would Win?]

The indominus Rex was able to communicate with Blue and her group Because she shared their DNA, but she also had T-Rex DNA in her as well. So, why didn't she just communicate with Rexy when she saw her? The Tyrannosaurus Rex would have made for a very formidable Ally next to the indominus Rex herself. Well here are some of our theories