Re: How do I manipulate bp_group_id() to have custom sidebars?
Have you tried the Widget Logic plugin? You can determine the placement of widgets using both WP and BP conditional tags. That means you can create custom sidebars for ANY component, category, tag, post, page, etc… Give it a whirl; it’s a lot easier than trying to code stuff from scratch 
https://wordpress.org/extend/plugins/widget-logic/
