Automatic Figure Numbering, possible to create a span like "Fig. X - Y"?

Hello,

I watched this tutorial and learned that you could create automatic figure numbering.

InDesign tutorial: Automatically updating figure references for books | lynda.com - YouTube

I'm currently writing my thesis and I have chapters where I have lots of images and have chosen

to use spans to free space and avoid the spreads from become messy looking.

I would like to:

1. be able to create a paragraph style that increases the numbering by 1, like "Fig. 1-2"

2. be able to create a paragraph style that increases the numbering by a freely chosen number, like "Fig. 7-10"

is this possible to do in indesign?

Best Regards

- Martin