BuddyPress.org

ooh, As I guessed, author url uses get_option(‘home’)
So, we will not need any extra code, just adding another filter will do the trick using our very first function.
`add_filter(“option_home”,”my_site_url”);

we are using the old function, just adding to work it for the home url too.
and I hope your filtering user domain is not causing any issue.