Though multiple PMDBs are running on the same endpoint, only one or two are starting up during seload.
When seosd is starting up, it will start up seagent and seagent will execute sepmdpull, which uses the token parent_pmd in seos.ini to know what PMDBs to start. If only one or two PMDBs are that endpoint's parent, then only those will be started during seload. If those PMDBs have parent_pmd set in pmd.ini, then those PMDBs will start as well.
To have another PMDB start when seload is called, add a line to the [daemons] section of seos.ini to start it. If there are muliple PMDBs to start, then add one line for each PMDB.
sepmd = /opt/CA/AccessControl/bin/sepmd -S SecondPMDB
sepmd = /opt/CA/AccessControl/bin/sepmd -S ThirdPMDB
sepmd = /opt/CA/PAMSC/bin/sepmd -S SecondPMDB
sepmd = /opt/CA/PAMSC/bin/sepmd -S ThirdPMDB