We learned how to go full width or show a sidebar on buddypress pages. But what if I want to specify *which* sidebar is shown on a page? This would allow me to choose a sidebar with content that is relevant for that page. Buddypress is so dynamic, choosing sidebars seems essential to the user experience.
What I did was take a page template that I liked, then made a copy of it and renamed it. Then I created a copy of the sidebar (and registered it with functions.php). Then, in the template copy, under sidebar, I swapped out the listed sidebar for my custom sidebar. Done. This way, you can have a page template with a different sidebar. Not sure if this is the ‘proper’ way of doing things, but it worked for me. Good luck.