If it's going to be three, then the chair represents the committee. The chair doesn't represent any single party here. The chair is appointed from a party but he represents everyone on the committee. So if it's going to be three, it should be the chair plus three members of the committee with one of those three members being a government member. That's all, if you want to have three. Otherwise you're going to get down to the chair plus two members of committee.
That's all.