If you have a bento box behind the stem you can but the junction box in there.
I used a 4-pot b-junction hidden in the stem then connected that to the 3-port a-junction in the bento box behind the stem. Wired up like this:
- L-extension, L-brake and R-brake connected to 4-port b-junc. hidden in stem
- R-extension with inline ANT+/B'tooth unit connected to 3-port a-junc. through the stem and into bento box
- 4-port connect to a-junc. in Bento box with short cable.
- remaining port on the a-junc. connected to rest of the system
I have 3 wires peaking out of the top-cap and into the bento box which makes the junction box very accessible