bad frame

i just got my 69 bird down to the shell and came across a bad rear frame from the drivers door back to the rear bumper it had worke done to it allready and was wondering if the whole rear frame can be replaced or not i don,t whant to put the car down.any help with this would be well appreciated thanks.len:(

i took a look at the frame on my 69 bird and the front sub frame is bolted but the back is welded in as far as i can see.