In the grouper.properties we have membership and group hooks defined... Each pointing to two or more classes. When running the PSP, we get the following error:
Problem loading class: edu.example.middleware.grouper.hook.GroupHooksImplExample,edu.example.middleware.grouper.namecheck.NameCheckHook
at edu.internet2.middleware.grouperClient.config.ConfigPropertiesCascadeCommonUtils.forName(ConfigPropertiesCascadeCommonUtils.java:547)
at edu.internet2.middleware.grouperClient.config.ConfigPropertiesCascadeBase.assertPropertyValueClass(ConfigPropertiesCascadeBase.java:1296)
at edu.internet2.middleware.grouper.misc.GrouperCheckConfig.checkGrouperConfig(GrouperCheckConfig.java:352)
at edu.internet2.middleware.grouper.misc.GrouperCheckConfig.checkGrouperConfigs(GrouperCheckConfig.java:315)

It appears that https://github.com/Internet2/grouper/blob/master/grouper-misc/grouperClient/src/java/edu/internet2/middleware/grouperClient/config/ConfigPropertiesCascadeBase.java#L1279 does not support a comma separated list of classes.

This appears to fail gracefully and the PSP runs to completion.