What I would recommend the committee do, if it's something that you are considering, is approach our provincial counterparts. Both information and privacy are joined in the provinces. On lobbying, my colleague in Ontario holds about seven hats. It might be interesting for you to speak to them.
The issue becomes institutional bias. How can you be requested something from the lobbyists, knowing possibly what a member of Parliament has disclosed to you? It's how you manage or create the walls to ensure that one set of information doesn't influence the other, although having the full picture sometimes might help.