Ways to even out plant sizes in time for flower?

1000 watt hps
6x6x6 grow room
Soil grow in 5 gallons
Fox farm nutes

So I have 6 plants, (3 plants = 7 inches, 1 plant = 4 inches, 2 plants = 2 inches) which are all doing pretty good, however; I would like them to all be able to flower at the same time. I'm LST the 2 inchers in hopes that it will speed up growing time. I can't throw them in another tent because my spot is too hot as it is and I dont want to top any of them. I am open to other techniques though (fimming, lst, scrog, etc) in order to slow or speed up growing time.

Thanks!

i think youv mentiond just about every way....other than moving the big plant into a different room, with less light so they grow slower..

raise the shorter plants closer to the light. Chances are you have all your plants in the same kind of pots and all your pots are the same distance from the light. If your seven inch plants are the proper distance from the light your 4 inch plant is three inches lower and you 2 inch plants are 5 inches lower. You are also using the wrong light to veg. hps bulbs are for flowering. you would be better off growing under 6100k fluorescents or metal halide. Remember light is governed by the inverse square law. Using 24 inches as how far away your tallest plant is from you light and assuming your intial lumens were 140,000 lumens the top of your 7 inch plant is getting 140,000 lumens/ 24 inches squared or 246 lumens per square inch. your 2 inch plants are getting 166 lumens per square in.