You can thank Boone for the answer below. Replace scope=groups with what ever filter you’d like to apply.
Changing the tabs is an appearance issue; it doesn’t have any effect on the activity items shown.
Try the following function in your functions.php or bp-custom.php. The logic is this: If the query string is empty (as it is when you first visit the activity page) and there is nothing in the POST variable that says which scope to show (that is, the user has not clicked ‘All Activity’ and thus set an AJAX request into effect), then show only my group content.
function bbg_my_groups_activity_default( $qs ) {
if ( empty( $qs ) && empty( $_POST['scope'] ) ) {
$qs = 'scope=groups';
}
return $qs;
}
add_filter( 'bp_ajax_querystring', 'bbg_my_groups_activity_default', 999 );