How do I get information about multiple employees by their id?

I need to fetch this info in one API call. This API works for me ( https://www.humanity.com/api/v2/employees/{id}), however I have to make multiple calls which takes a lot of time to fetch all the information. How do I fetch all in single API call?

Also, is there a way just to fetch one or two fields from employee information. For eg, I just need the unique_id field, but I have to fetch the whole information which again takes lot of time if there are like 10 employees.