Rest Sensor — update if and only if a specific attribute has changed?

The Rest sensor has this option:

force_update boolean (Optional, default: false)

Sends update events even if the value hasn’t changed. Useful if you want to have meaningful value graphs in history.

The API I’m checking with has a timestamp (which is part of the returned JSON; I’m using json_attributes to load it and other metadata into a sensor attribute). There may be times when the value has not changed, but the timestamp is updated. I’d like update events in this case, but not otherwise. That way, update events in HA (mostly, at least) correspond to real updates on the remote side. Is there a way to do this?