Does anyone know of a way to find out the ring time of a call as soon as it has been answered (ie: without waiting for the call to be completed, when it’s part of the standard CDR record)?

I’m looking for a way to place a call, wait for it to be answered, and then perform different actions (eg: bridge the call to another number) depending on how long it took for the call to be answered (eg: less than X seconds or more than Y seconds).

Anyone got any ideas (for any reasonable version of Asterisk)?