I have an option that may or may not be viable to you :P. All depends on how much the situation is worth to you.
You couuld cut just before where the tomatos are (yep, cut the whole thing off) depending on what is infront of it and if the roots from that is tangled up with the tomatoes/if the plant is sacrificable.
Then you can splice on a new piece of piping to replace the cut off section. I think there wasn't anything else running through that part of the system if I remember the pics right.
Slice the cut out section doewn the center on the bottom with a rotozip/dremmel/other orbital cutting device to try to make only minor cut and minimize your damage to the roots. Repeat the task on the top and you have the plants free. Then you just need somewhere else to put them :P
It is an option. I don't know if it is a viable option for you or not, but it is a possibility, and might prevent problems with water not moving properly and causing other problems with the plants.