Changing pipe slopes

I have created a large sanitary sewer pipe network with about 120 pipes total. As I receive updated survey information and changes from the client, I need to change some of the pipe layouts from time to time. Changing them horizontally is no big deal because I can just drag the structures around and the pipes go with them. But I also need to change the slopes of many pipes in a sequence. For instance, pipes 50-85 might have been at a .5% slope to begin with, but now I want that series of pipes to be at a .4% slope. Is there a way to change the slope for multiple pipes and have the invert elevations at the structures adjust correspondingly? All I've been able to figure out is to adjust each pipe individually, which takes forever in such a large network.

Basically want I want to do is start with one pipe where I know what I want the invert elevation to be, and then adjust the slopes of all the pipes from that point on without changing the invert elevation at that beginning point.