The structure is bit weird. That isn't how a native speaker would write it. There is a main building containing several rooms, the most impressive of which is the 'Royal Suite.'

I would say there is nothing wrong with your sentence, but not the most direct way of saying things. A comma after the among which, might add a bit of a "pause" and "drama" to the unveiling of the Royal Suite, if that is the effect of what you are trying to say. Small nuances in writing styles...

It was clear what you were trying to say, I think you used the Spanish sentence structure which doesn't always work in English but it wasn't hard to understand. The verb 'to contain' will help you here.

I guess it is better to say: The rooms are in the main building, among which the most impressive is the ‘Royal Suite’. Do you understand now what I want to say?

its completely wrong to the point that i even did not get its meaning