/pillar/test/init.sls

portal:
  users:
    testdude:
      mainmail:
        - test@mail.com
      secondmail:
      flags:
        - flag1
        - flag2
        - flag3

    anotherdude:
      mainmail:
        - mail1@abc.net
        - secondmail@abc.net
      secondmail:
      flags:
        - flag1
        - flag2
        - flag3


    anotheruser3:
      mainmail:
        - john@hotmail.net
        - george@hotmail.net
        - helen@hotmail.net
      secondmail:
      flags:
        - flag1
        - flag2
        - flag3




test.cfg:

emails= {% for portal, data in salt['pillar.get']('portal:users').items() %} {% for mail in data.mainmail %}{{ mail }},{% endfor %}{% endfor %}





state/test/init.sls
test_config:
  file.managed:
    - name: /root/test.cfg
    - source: salt://test/test.cfg
    - template: jinja




results:

cat /root/test.cfg
emails=  mail1@abc.net,secondmail@abc.net, test@mail.com, john@hotmail.net,george@hotmail.net,helen@hotmail.net,

As you can see from results, if a "key" contains more than one value then the values are returned as array. Is it possible to get the items as seperate result in order to manipulate-use them.