PeoplePlanner can only associate a single appointment with an employee.
There are two ways to integrate between SelectHR and PeoplePlanner:
DataHub
It is not possible to decide which appointment takes precedence when using DataHub.
It's worth noting however, the most recently entered/effective appointment in SelectHR will take precedence in PeoplePlanner, if this is not wanted (as it may be a less significant role), you will need to alter this manually in PeoplePlanner.
Click Job title.
Delete the unwanted job title.
AIS
If you are instead using Access Integration Services, then you can use the following instructions to set the preferred appointment in SelectHR:
Open your HR Menu set.
Navigate to: Admin, click Additional.
Click Accounts and Rostering, then Rostering Links.
Click into the item for PeoplePlanner integration.
Click the Link Employees tab.
Drill into the employee.
Choose the linked appointment, then click Save.