Checkbox listens to two comboboxes

Ok, I have this checkbox that listens to one combobox. I want to add another combobox so when checkbox is checked/unchecked, both comboboxes are disabled / enabled. How can I do that?

Checkbox: new Ext.form.Checkbox({
            checked: true,
            listeners: {
                check: function () {
                    that.fields.ComboBox1.setDisabled(!checked);
                }
            }
        }),