Default theme - 2nd sidebar for within groups for group specific info

Getting my hands dirty in code and just wanted to sanity check before getting too far.

Working with BuddyPress; WPMU 3.0.1; Default theme.

For the main pages in BuddyPress I have used the sidebar to show the Groups, who is online and members widgets. Good general stuff. However, it's been requested that when members go into a group the sidebar is used for more group specific stuff.

So, in the default theme (once I've tested it all out next step will be create a child theme, I promise) I have:
1) added a second widget column in functions.php:
/* Register the widget columns */
register_sidebars( 2,
'name' => 'Sidebar %d',

2) changed the default reference in sidebar.php to the numbered version:
<?php dynamic_sidebar( 'sidebar 1' ) ?>
3) stalled...

I guess the next step is to change the call in groups/singe/home.php to 'sidebar 2', but as it currently just does this through sidebar.php wasn't sure if I should create a sidebar2.php or use some sort of switch within sidebar.php to call the correct one.

My follow up question is possibly even more pertinent and may put kibosh on the whole plan if not possible - how do I get the widgets to behave/use data in group specific way, i.e. tags/latest post from that group's blog?