For anybody that's interested - I found a way to manage my group using an addon called XMacros http://rift.curseforge.com/addons/xmacros/

It allows you to create customizable buttons and macros that are visible while in a vehicle. The down side is, you it doesn't allow hotkeys so functionality is limited for boxing. I created two buttons with basic follow/assist macros and use a simple repeater region to pass the clicks. It's a fairly ghetto solution, but I've managed to clear the vehicle phase of SBP, which is all I really wanted it for.