How can I get all groups a user belongs to using Okta's API?

I'm trying to sync users/groups that sit behind Okta in Active Directory. Specifically, I'd like to get all groups a user belongs to, upon login to a third party application.

Looking at the Okta API documentation (http://developer.okta.com/docs/api/resources/groups.html) I see that I could accomplish this by performing the following operations (in pseudo-code):

FETCH ALL GROUPS (using List Groups operation)
FOR EACH GROUP
    FETCH A LIST OF USERS (using List Group Members operation)

For my purposes this seems very inefficient, but I can't find a better way of doing this by looking at the documentation.

Ideally, what I would like to do is:

FETCH ALL GROUPS FOR A GIVEN USER ID

Is there any way I could accomplish this ?

Any help is appreciated. Thanks.

I found the answer: the Get Member Groups API call does this exact thing. It's under Related Resources here: http://developer.okta.com/docs/api/resources/users.html