I don't know if you could do that, but even if you can, I don't think it would work the way you hope.As I understand the tactical situation you present, yes, you would blast the crap out of their shields on the way in, but once you pass them they are presenting a fresh, likely undamaged shield facing to you which will absorb your rear-fired torpedo with little to no ill effect.
In the beginning can you put 2 phasers in the foreward slots and then the torpedoes in the back slots?
Because then if you come in from the front blasting with phaser it should weaken shields enough to drop torpedoes as you pass. Would that work?
Doing that to a moving target that knows what to expect would be difficult. If you do want to try something like that, I'd recommend against going straight and trying to maintain a broadside more to the rear of your vessel. That'll give you more time to use your rear launchers when you wish to try. It'd probably be better to fit the launcher to front though. Even if it means having a ship blowing up in your face, it'd be more intuitive than trying to use the rear launcher while pulling away.
Dont forget, this is SPACE combat. I've found being directly above your target works best. It counts as a broadside AND frontal torpedos still work. With a slight touch of acceleration, the rear ones work too. The thing I like most is, a little shift to the right, and you're on the target's right side shield, a little shift to the left and you're on their left side shield...rinse and repeat for fore and aft...slow and speed up. The enemy cant turn under you to get a different facing, he cant fly over you, and the enemy AI is such that they think VERY 2 dimensionally so they wont dive or climb to change their facing.