Why not get to the meeting early and unseen quickly pin an envelope with a card in it to the KH noticeboard with instructions written in big letters on it for it to be given to the C/O.
The COBE or another elder will see it, take it from the noticeboard and give it to the CO who will likely put it away to be opened when he gets home.
When he gets home he will open the card and you can have anonymously written:
Dear (name)
I wanted to write a few lines to say how much I appreciate your self sacrificing attitude for the brotherhood and how encouraging your visits are. Sadly this is not true. How you can promote the support of an organization which fails to report child molesters to Caesar and promote the support of the risable doctrine of "overlapping generations" that saw 1914 is beyond me!
Therefore instead of giving yet more dollars to a representative of a cult that lives off of members donations anyway I have sent $100.00 to a more worthy cause.
Yours truly,
An anonymous member of your circuit.