I have the helix and don't think I even need the 11r anymore (thinking of selling it since Ive not played with it since last year when I got the Helix) but if your determined to hook um all up I would use the helix as the primary rig and utilize the FX loops on the helix since it has so many options like you could connect them with midi and use fx loops and control any midi commands that the other two FX boxes have that may be controlled with midi through "snap shots" on the helix to make all changes.

this was just posted by line 6: US2 Using Helix To Control External Gear Line 6