[seandkendle]

What about: BP_Groups_Group::group_exists( $group_slug )?

	 /**
	 * Get whether a group exists for a given slug.
	 *
	 * @since BuddyPress 1.6.0
	 *
	 * @param string      $slug       Slug to check.
	 * @param string|bool $table_name Deprecated.
	 * @return int|null Group ID if found; null if not.
	 */
	public static function group_exists( $slug, $table_name = false ) {
		global $wpdb;

		if ( empty( $slug ) ) {
			return false;
		}

		$args = array(
			'slug'              => $slug,
			'per_page'          => 1,
			'page'              => 1,
			'update_meta_cache' => false,
			'show_hidden'       => true,
		);

		$groups = self::get( $args );

		$group_id = null;
		if ( $groups['groups'] ) {
			$group_id = current( $groups['groups'] )->id;
		}

		return $group_id;
	}

class-bp-groups-group.php line 715