Getting a plugin group plugin from the main plugin fails in Initialization

This may have been a conscious decision, but the plugins that we use to install widgets, sql etc are not usually the ones that are used for functionality.  We usually have a Core plugin that manages the functionality outside of installation.  So we have something like this. 

CorePlugin  - Plugin Group
        SQLScriptInstallerPlugin - Child Plugin Does SQL installation and stores connection string

However, it seems if we call "PluginManager.Get<SQLScriptInstallerPlugin >()" as we now need to get the connection string and schema from the Initialize of CorePlugin it returns null?