Although I don't pay for the fees personally, we have the same problems in the corporate world. Not only do we have to pay excessive landing, parking, towing and handlings fees, but we also have to put up with charges that would make Dick Turpin blush!
I recently complained about excessive charging at one particular European airport that we visit regularly. In this particular destination we do have a choice - the alternative is 30 ks away for the pax, but the charges are FAR less (in our case 800 Euros.less).
I mentioned this to a couple of other operators who use the same airport/handling agent, and suggested that we complain in bulk. Hey presto - charges for us were reduced by FIFTY percent!
Jump on the bandwaggon guys - if they don't want to play fair - dessert them, but get your mates to do it with you. At the moment they need you more than you need them, so make hay while the sun is shining.