Tata Pairings?

Why is it that some stong GM's like Tiviakov, Naiditsch and Edouard etc don't make it into group A, and how do certain players qualify for group C even thouigh they not GM's?

"Certain players" are Dutch players who are granted the opportunity to play a strong tournament in their country.
The first group is probably too strong for Sokolov,Van Wely and L'Ami but they are Dutch.
I read somewhere that Harikrishna plays because he won Group B last year.I don't know if it's true.The rest certainly deserve to be there.
The 3rd group is designed so that Dutch players(and not only) that are not IM will have the chance to do a norm.

The decision "who plays where" belongs to the ones that pay.
Isn't that always the case?