I have a form that loads one record from a database for editing/updating purposes. This form contains one JsonStore. In addition, I have a combobox attached to this form with a second JsonStore. The second store is used to get a list of all available values which are in a separate database table.

The first store (table 1) contains a foreign key to the second store (table 2). If this were PHP, I would do something like the following in the option statement of the select to set the default option.
PHP Code:
if($table1['myID'] = $table2['myID']) { echo "<option value='somevalue' default=default>displayVal</option>"; } 
So when I load my form...
Code:
editSwitchForm.getForm().load({
                    url: 'get-switch-data.php?id=' + e.attributes.id,
The responses match up with the layout defined in the form.

I then load my combobox with
Code:
buildingCombo.store.load();
Now what I need to do is get a field/value from the editSwitchForm response and set the default option of the buildingCombo.