I am pretty sure that I am hearing the 3rd beacon that Token alerted me to and it is distinctive. A fast dit that sounds as if it goes up in frequency a little and the PX3's display seems to show that. Maybe a 2 dit/sec rate?. Currently centered at 6626.420 KHz. Local time is 17:05 PST
Many of these beacons move around a bit in freq, so the relative frequencies of this trio can be different at different times.
Here is a spectrum shot of Rocky, Rainy, and the Unknown ditter. At the time of this image Rocky was centered on 6626.7, Rainy on 6626.4, and the Unknown at 6626.2.
I think this unknown has been there a while, just not reported. I would have to look at old SDR recordings to try and come up with a time frame, unfortunately Rocky / Rainy is one I tune to often, but almost never record.
T!