How to add a predefined filter for standard endpoint?

[NielsDeGroot]

I would like to add an additional predefined filter to the following end-point or change an existing filter
portal/person/reports/datamodel
OptionalClauseProviders.Add((IPredefinedFilter) new PersonIsInternal());
Did not find an example in the 'ApiSamples' folder.
If this is possible I would greatly appreciate some code examples.

Thank you,
Niels