I know that no one exercise can help the posterior chain than GHR's, but can there be some other combination so i can hit this area just as effectively? I dont have a GHR.
NGHR or band assisted NGHR
I guess i could just get some one to hold my feet and do it that way. Makes sense.
If you plan on doing them unassisted, they are very very hard. You can do negatives, but be sure to catch yourself before you bust your nose.
You can also use a barbell with a pad or something to hold your feet.
Using the barbell sounds good, it wouldn't be awkward like someone holding my feet in that position. I'm sure i can rig something for assistance in that health club i go to.
ball leg curls
sometimes you can use the lat pull down or the seated cable row machine. depends on the set up of the machine...
I found a set-up similar to this works best for me. It makes a big difference if you have a 'toe-plate' or other means to brace the foot. I do them backed up against a wall, this guy uses the frame of the machine. I also do some calve raises before these.
When I was at a commercial gym I used the lat pull down by kneeling on the bench and hooking my feet under the knee pad.
At home, I do this: http://www.youtube.com/watch?v=6D3mN6tjGto
Looking at the video above, I wish I had a squishy half ball. Those look easier on the knees.