You know, people always say if you have a 50 + 85 it's redundant or a 24 + 35, or a 35 + 50, etc.. etc.., if each gets used for different purposes the it isn't redundant. It would be redundant if you use both for the same exact thing and get very similar results. If the 135 is the portrait lens for head shots and the 85 is the portrait lens for full body shots, or whatever each use is for then keep them both.
Btw, most people do not consider the 85 + 135 combo redundant as they are pretty far in terms of focal length. The holy trinity for some people is the 35, 85, 135 combo (or 24mm).
Anyways whatever you decide to do, goodluck to you!