bp_get_possible_parent_groups( int|bool $group_id = false, int|bool $user_id = false )

function bp_get_possible_parent_groups( $group_id = false, $user_id = false ) {
	/*
	 * Passing a group id of 0 would find all top-level groups, which could be
	 * intentional. We only try to find the current group when the $group_id is false.
	 */
	if ( false === $group_id ) {
		$group_id = bp_get_current_group_id();
		if ( ! $group_id ) {
			// If we can't resolve the group_id, don't proceed with a zero value.
			return array();
		}
	}

	if ( false === $user_id ) {
		$user_id = bp_loggedin_user_id();
		if ( ! $user_id ) {
			// If we can't resolve the user_id, don't proceed with a zero value.
			return array();
		}
	}

	// First, get a list of descendants (don't pass a user id--we want them all).
	$descendants = bp_get_descendent_groups( $group_id );
	$exclude_ids = wp_list_pluck( $descendants, 'id' );
	// Also exclude the current group.
	$exclude_ids[] = $group_id;
	$args = [];
	$args = bp_parse_args( $args, array(
		'orderby'         => 'name',
		'order'           => 'ASC',
		'populate_extras' => false,
		'exclude'         => $exclude_ids, // Exclude descendants and this group.
		'show_hidden'     => true,
		'per_page'        => false, // Do not limit the number returned.
		'page'            => false, // Do not limit the number returned.
		'user_id'         => $user_id, // get loggedin users groups
	), 'get_possible_parent_groups'  );

	$possible_parents = groups_get_groups( $args );

	return $possible_parents['groups'];
}