Here's some documentation for your Bose System:
Serial Effects - excerpt from the manual
And then the
Alesis NanoVerb Manual.
Edit: It looks like the signal path for the Picoverb is the same as the Nanoverb. Here's the Alesis PicoVerb Manual.
From Chapter 2: Connections
From Page 12
Blue "Ring" is Send from the Bose System
Purple "Tip" is the Return to the Bose System
From Page 15:
It seems that with the Nanoverb you can use two channels when you operate in "stereo" mode. But you cannot control the left and right channels independently. So you can maintain the separation between the channels but not have them running different levels, mix, or effects.
EDIT: Note - you will need an INSERT cable for each Bose Channel you want to run through your effects unit. (up to 2 max).
See the original discussion: