drain/venting question

[rbird7282]

I am currently redoing a bathroom and have a drain/venting question.The toilet is about 2' from the 3" stack. The 3" stack has a 1 1/2" vent coming out of the top of it (just above the toilet tee)and through the roof. There is a shower and lavatory that tie into the 3" toilet line and both are vented with above where the lavatory drain lineties in. I have no problem venting the new lavatory and shower, but the toilet need to move to the other side of the bathroom. I will be about 4' from the stack. I want to know if I can get rid of the vent coming out of the top of the stack above where the toilet ties in, and add a vent in the 3" elbow for the toilet. This vent would go up a new wall and tie back in to the existing in the attic. I have no problem adding a vent, I just don't want it to be in the same wall that it is now. Any help would be greatly appreciated.