1.js

var data = {
  type: "something",
  name: "whatever",
  addresses: [
    {
      type: "read_address",
      address: "1/2/3",
      value: "10"
    },
    {
      type: "write_address",
      address: "1/2/4"
    }
  ]
}

2.html

<script id="my-template" type="text/template">
  <p>type: <%= type %></p>
  <p>name: <%= name %></p>
  <p>read address: <%= _.find(this.addresses, function(addr){ return addr.type == "read_address" }).address %> </p>
  <p>read address value: <%= _.find(this.addresses, function(addr){ return addr.type == "read_address" }).value %> </p>
  <p>write address: <%= _.find(this.addresses, function(addr){ return addr.type == "write_address" }).address %> </p>
</script>

3.js

var viewHelpers = {
  getAddress: function(type){
    var address = _.find(this.addresses, function(addr) { 
      return addr.type == type 
    });
    return address;
  }
}


_.extend(data, viewHelpers);

_.template(myTemplate, data);

4.html

<script id="my-template" type="text/template">
  <p>type: <%= type %></p>
  <p>name: <%= name %></p>
  <p>read address: <%= getAddress("read_address").address %> </p>
  <p>read address value: <%= getAddress("read_address").value %> </p>
  <p>write address: <%= getAddress("write_address").address %> </p>
</script>

5.js

Backbone.View.extend({
  template: "#my-template",

  render: function(){

    var data = this.model.toJSON();
    _.extend(data, viewHelpers);

    var html = _.template($(this.template), data);
    this.$el.html(html);

  }
});

6.js

Backbone.Marionette.ItemView.extend({

  template: "#my-template",
  templateHelpers: viewHelpers

});