Nested data in ExtJS

Nested data in ExtJS

I download several entities one ajax-request. Then i add them to stores. I
need to commit a changes alike one ajax-request. How properly to do it?
Json structure:
{
entity1: [],
entity2: [],
entyty3: []
}
success: function(responce) {
var data = Ext.decode(response.responseText);
store1.add(data['entity1']);
store2.add(data['entity2']);
store3.add(data['entity3']);
}