Using one Dropdown for two fields

Hi Gurus
I have an issue. I have a dataset connected to a repeater. I habe implemented a couple of Dropdowns which work fine. Now I would like to have the values in two different fields populated in ONE drop down. I am kind of desperate as I cannot figure it out.

please help - I neeeeed somebody

Nayeli (Code Queen) has an excellent tutorial that you can have a look at for combining values into one field using checkboxes.
https://codequeen.wixsite.com/checkboxes
https://www.youtube.com/watch?v=kc1YBFG2tXA - Youtube video of tutorial.