5.1 lollipop - How do I exclude a subfolder in DCIM from Google Photos backup?

I set Google Photos to automatically back up pictures and videos I take and nothing else. I use an Xperia phone and it comes with a feature to take "Time Shift" photo which is essentially just a series of rapidly taken pictures. It's stored under the "XPERIA" folder inside "DCIM". The problem is it doesn't show up in the setting to exclude folders. And it also gets uploaded to Google Photos, so I'm often flooded with pictures (remember, it's multiple rapidly taken photos) that I don't really need backed up. I can't move the folder either as it is hard coded into the Xperia's system.