Hi lnuanez,
Unfortunately, there's no single REST API call to accomplish exactly what you're asking for. However, you could use our Studio Endpoints tool to create your own custom endpoint that would produce the response desired. The same number of REST API calls would still be made; however, those calls would be made on the Lithium application side instead of on your side. Thus, the endpoint serves to encapsulate all of the calls into a single method.
If you don't already have Studio Endpoints enabled on your community, I'd suggest filing a case with our Support team so that they can assist in having it enabled for you.
Regards,
Adam
