Finally figured out how to do it:
cfg: modparam("acc", "db_url", DBURL) ... modparam("sqlops","sqlcon", CBDBURL) ... modparam("sqlops","sqlcon", ASGDBURL)
and startup:
kamailio -f /etc/kamailio/kamailio.cfg -E \ -A 'DBURL="mysql://admin:mypass@db.mydomaincom/kamailio"' \ -A "CBDBURL="cb=>admin:mypass@db.mydomaincom/kamailio"" \ -A 'ASGDBURL="asg=>admin:mypass@db.mydomaincom/kamailio"' -DDDD 2>&1
Now let's try and put that on the startup systemd script.