Hoi from Amsterdam! You can now create labels, you can see them as categories, then add as many of these to individual reviews as you want. This allows you to them create widgets that only include reviews that have certain tags. This allows you to create widgets with a selection of reviews.
How it works:
Create as many labels as you want, see them as categories or groups. After creating them, you can add these labels to individual reviews and video testimonials.
Once you've done that, you can create a new widget, and choose the labels you want to include. It will automatically show all public reviews that have those labels.