Ext Js - Nested Xtemplates

I am new to ExtJS development. I have data from 2 different data stores (ex: DepartmentsStore and EmployeesStore). I am trying to show up list of departments in a parent table and

Solution 1:

It looks to me like you are returning a string from an asynchronous function when you do appEngine.autoPost. For this to work, your renderEmployees function needs to synchronously return the string. XTemplates have no concept of an inner function returning a string asynchronously.