I think that Geary says that he's leaving to chair a meeting of "my own committee". It COULD be that he's the chairman of some other committee, and calls that one his own committee, but in that case he would have the ability to schedule things as he pleased.

In a practical sense, if Geary was a member of the committee, then he would have to sit through the whole thing. It would be very suspicious, to either the press or to Michael, if he bolted the televised organized crime hearings to go talk about wool subsidies or something.

It does make sense, though, for Geary to extract a few minutes with the microphone when his constituent was the target of the investigation. Even if he were honest, committe counsel would probably have been overjoyed to find some way to deflect that he was being unfair to Michael.