How to configure the Domino to Exchange directory connector to only pull Domino users that have the "Mail System" set to "Notes".
Right click on the connector and choose "Advanced Settings...", then select the "Custom Configurations and Filters" tab, then click add and add the following:
Key = person-search
Value = (mailsystem=1)
Then click ok and save and activate the configuration. Then run the connector.
If you already have a person-search filter you will need to merge the syntax.