Merge request of users

I have a list of users I want to get all merge request of them, I thought about using List project merge requests but this is get me all the merge request and then i need to filter them by the merge by id. I know that by default its get all merge requests the authenticated user has access to. By default it returns only merge requests created by the current user. is there a filter by the API for users and project?. or is that possible to get all merge request for user just by a user id and without using his credentials just his id (note I will use admin role to retrieve them.)

For posterity/reference, the API endpoint you’re referencing is Merge requests API | GitLab

The above endpoint supports passing an author_id or author_username parameter as a filter in the request (see listed examples in the link above), which should work in combination with an administrative level authentication to provide back all merge requests. Does this help?