Merge Only In Deep-Nested Objects

[cadencelabs-master]

Let's say I've got an object with the below structure (in toJSON):
order: {
item: {
product: {
name: "foo"
}
}
}

Sometimes I may want to return response data from the server to update the name of the product BUT NOT to completely reinitialize it. As it stands currently, if I send back any information for "item" it is completely reset as if it were a new model. Is there some way to specify that I want nested information to be "merged" as opposed to completely overwritten?