Yes, the way you're doing it is more realistic: xtypes inside a formpanel. So you'd have something like:
Code:
form = new Ext.form.FormPanel({
items: [{
xtype: 'fieldset',
title: 'Edit Message Pref.',
instructions: 'Edit your Settings',
defaults: {
required: true,
labelAlign: 'left',
labelWidth: '40%'
},
items: [{
xtype: 'fieldset',
title: 'General - Entire City',
items: [{
xtype: 'checkboxfield',
Align: 'left',
name: 'cc0',
value: true
}, {
xtype: 'selectfield1',
store: myStore,
displayField: 'text',
valueField: 'value'
}, {
xtype: 'selectfield2',
store: myStore
}]
}]
}]
});