Allowing configuration of mysql_replication_hostgroups in proxysql.cnf, rather than requiring admin SQL commands to configure them would allow proxysql to more easily be operated in an automated manner, in particular in dockerized environments where containers are expected to start up and be useable completely hands-off.
My current workaround is to build my container with a seed sqlite3 database containing that particular table with the row I need the passing the --reload flag on startup to get proxysql to merge my .cnf based configuration with my desired replication hostgroup configuration.
Thanks for considering.