Polymer iterate/repeat through multiple ironajax responses

I want to iterate through 2 arrays including data from iron ajax request.

The 2 repeats are:

  <template is="dom-repeat" items="[[riskNamesArr]]" as="risk">
  <paper-listbox multi>
  <paper-material>{{risk}}</paper-material>
  </paper-listbox>
  </template>

   <template is="dom-repeat" items="[[riskWorkflowStateArr]]" as="state">
  <paper-listbox multi>
  <paper-material>{{state}}</paper-material>
  </paper-listbox>
  </template>

The result is then

{{risk1}}
{{risk2}}
{{risk3}}
{{state1}}
{{state2}}
{{state3}}

My issue is that I want to iterate through both arrays at the same time to get something like that:

{{risk1}} + {{state1}}
{{risk2}} + {{state2}}
{{risk3}} + {{state3}}