Import Activity From Other Devices Into Custom Diary Group

I have some custom diary groups setup, one in particular being 'Biometrics'. I like to put all of my measurements and readings into here. I recently got a FitBit and started having it automatically import my sleep and heart rate data. Unfortunately however it seems to go into the default first group, which in my case is 'Uncategorized', and there is no option to specify.

For now I'm going to try moving diary groups around to see if it's just defaulting to the first one, but the ability to choose would be great!