In playbooks, each pattern stanza can reference it's own user to run as, so you can

run things as multiple sets of users (if you want) in the same playbook.

examples/playbook.yml

@@ -1,9 +1,6 @@
 - pattern: '*'
   hosts: /etc/ansible/hosts
   tasks:
-  - do:
-    - restart apache for kicks
-    - command /sbin/service apache restart
   - do:
     - configure template & module variables for future template calls
     - setup a=2 b=3 c=4