Associating Users with Their Groups

I’m new to the world of APIs, so please excuse any incorrect terms or beginner-level nonsense.I’m accessing the SalesLoft API to extract my organization’s data on a regular cadence, and ran into the following issue. 

The way I currently have my python script set up, I first call the activity_histories endpoint to get a list of activities with my desired types and time range. Then I pull the user guids (direct), call or email id (from static data), and person ids and/or account ids (based on resource type and resource id). For each person id, I call the /people endpoint to get the associated account (in case it isn’t in activity_histories for some reason). For each account id, I call the /accounts endpoint; for each call id I run through the /calls endpoint to get sentiment and disposition; for each user id I run through the /users endpoint to get user names etc. I call the /successes endpoint to get the person ids associated with all the successes for the date range I’m looking at. I then put all of this in a flat table to make it easier to work with. TLDR: I use /activity_histories as my fact table and /users, /calls, /emails, /people, /accounts, and /successes as detail tables.

Now, however, I want to have a column to say the group name that the user is in. However, for some reason the /users endpoint only has group id as an input, not an output. I’m wondering if there’s a way for me to associate the group name with the users in my current setup, or if I need to restructure my script. Any help would be greatly appreciated.