Is it possible to set up a mining operation that routes only particular txns?

[nebulus]

Okay, ASICMINER hardware auction just ended and that gave me a vision of the future where AM dominates the transaction routing business. Now, I know a few things about mining and I used to mine pretty happily back in 2011 without giving it much thought.

However, my knowledge got rusty...

Is it possible for a mining venture to filter out transactions that it is routing based on a particular set of rules? Is that a problem? For example, in the vision I mentioned before, ASICMINER had partnerships with some kind of enournmous futuristic financial institutions, where it routed particular transactions and ignored the rest! Appreciate your thoughts, yays or nays...