Is there a way to get the fields of the relationships in the rest api V8

I can get the relationships of a record to a subrecord but is there a way that I can immediately retrieve the fields of the related records? Now if I want to get the fields of the related records, I need to first get the list of related records and then get the fields for each record individually so it would be nice if I could get that data in one go.
Best regards,

Is there any solution for this?

I have the Account ID, I want to retrieve the related Contacts and specific fields in one API call?

I was hoping it would be this:


Is there any way to avoid have to make individual API calls to each Contact?