If I may, Mr. Chair, on that point, to my mind there are essentially two separate issues here: whether the motion can move forward; and if the motion is adopted, what process does the committee follow when it's asking questions?
I would advise the committee to be cautious at all times when dealing with an issue that is before the courts. That said, there's nothing that prohibits the committee from inviting this group to appear, and there's nothing that prohibits the chair from a ruling one way or the other.
Again, if the chair rules either admissible or inadmissible, any member could challenge that ruling. That said, I would advise caution, based on the idea that the committee wants to make entirely sure that it does not appear to be trying to influence or prejudice the process currently happening before the courts. It's really up to the committee to decide how it feels it is appropriate to exercise that caution.