One plant would have given you a better harvest in that pot, Kevin. But now that they're going, as Deb says, cut off the innermost ones of the group carefully, leaving maybe two or three total. Keep them moist - I would think you'll need to water morning and evening to keep those plants alive through the hot weather in that pot - and fertilize!
Next year when you start tomatoes, remember Only One Plant Per Pot! Plant just a few seeds in each pot, and thin out extra plants while they are tiny.