Recently, I went on a trip with 2 bikes and 2 pillion for a total of 4 Sena SLR headsets (we all have Shoei Neotec 2 helmets).

We about drove ourselves crazy trying to figure out how to pair the headsets so we could communicate as a group. We ended up with an easy fix that worked for us. Basically we wanted to be able to communicate this way: Driver to Pillion, Driver to Driver, Pillion to Pillion.

The way that the Sena SLR pairs as stated, Last one you pair becomes the 1st on the list intercom. (What I mean is When you tap the center button one time, you will connect to the last person you paired with, Tap the center button twice and you will intercom with the next to the last person you paired with.)

So for the Drivers: Both Driver headset you had to repeat the following process to achieve the pairing order of: one tap = Driver to Pillion, two taps = Driver to Driver:
1st, pair the Driver to the other Driver, next pair the Driver to your own Pillion.

For the Pillions each headset: Both Pillion headsets you had to repeat the following order to achieve the pairing order of: one tap = Pillion to Driver, two taps = Pillion to Pillion:
1st pair the pillion to pillion, 2nd pair the Pillion to Driver.

Anytime a Driver taps the center button one time on the SLR he/she connects with their Pillion. When a Driver taps twice on the center button they communicate with the other Driver.

For a Pillion: 1 tap connects to their Driver... 2 taps they can communicate with the other Pillion.

I hope this did not confuse you more... The hard part was to realize that EACH headset has to be paired in the correct order.