I have done this, but was extremely careful to not water for a few days before or after, do it when as cool as possible, dig wide, carefully separate the entire root ball, keep roots as stable as possible, carry by the thickest part of the stem, unwind knotted stalks instead of cutting them, rebury them deeper than I took them out, stake them very well in their new location, and give them a deep, deep fert drench a day or two later.

Others have given the advice that tomatoes grow like weeds, and if the nutrients in the ground are all right, you can't kill them if you want to. Many stories on GW talk about deer eating them down to the ground or wind ripping them out by the roots, and still getting a fine harvest.

Someone in the past mentioned just cutting half of them at soil level and rooting the base stalk deeply without it's root bulb in place at all. The advantage here is you only risk the survival of half of your plants, instead of the entire crop by messing with the entwined roots.

If I was in your situation today, I might just consider some deep pruning and additional vertical support and leave the plants in place. With indeterminate varieties, you can limit the number of fruits by reducing to a single stalk, but produce better and larger fruit for a longer season.

What variety and how close are they?

Sorry, no hard and fast rules here. I bet you've learned a lesson for next year, though! Check with the tomato forum - there's a lot of 'mater geniuses over there that don't read this forum.

Good luck!