Retrieve entity and corresponding access in same query

I have a solution that synchronizes Dynamics account data and security to an external system. 

This solution is connecting to an Office 365 Dynamics installation.

So far I've manage to get following logic working:

1. Retrieve all accounts with the RetrieveMultiple function

2. Retrieve all users with the RetrieveMultiple function

3. Foreach account

3.1 Foreach user

3.1.1 Retrieve RetrievePrincipalAccessRequest for accuntId and userId, and parse access to external format 

This works, however the solution is very slow and requires three (atleast) calls to Dynamics.

My question is: Is it possible to write a single RetrieveMultiple QueryExpression (or other) which will contain all account with all users and corresponding accessrights (create,read,assign etc)?

Best Regards,

Marius