You could have a texture that always matches to the next pipe (say on map channel 0) then have a blended texture for the between area on map channel 1 where you could vary the tiling.
For my project, I am building a set of modular pipe pieces with different diameters. Currently all of the UVs are square-mapped from the 0-1 range so the pieces are perfectly tileable; however, depending on the thickness of the pipe, its UVs may be stretched too thin or too far on the V axis. I could scale the UV shell…