Re: Changing BuddyPress Base URL
The “members” slug, as it is called, is also autogenerated and does not represent an actual, physical space. The easiest way to do this would be to change the slug to “usa/members”. See this article, https://codex.buddypress.org/how-to-guides/changing-internal-configuration-settings/ , and scroll down to the section entitled “Change the URL slugs of BuddyPress components”
Basically, you would add this to the wp-config.php file. Having never tried adding a forward slash to a slug, I’n not sure if it will be stripped out, but on the surface, I can’t think of why that should not work:
define ( 'BP_MEMBERS_SLUG', 'usa/members' );