presto-main/src/main/java/io/prestosql/SystemSessionProperties.java/SystemSessionProperties/isEnableForcedExchangeBelowGroupId
class SystemSessionProperties:    public static boolean isEnableForcedExchangeBelowGroupId(Session session)
    {
        return session.getSystemProperty(ENABLE_FORCED_EXCHANGE_BELOW_GROUP_ID, Boolean.class);
    }