Some background; This is my first time GMing and I'm running a Homebrew campaign that doesn't drastically change the mechanics. However, depending on the design choice someone picks (which can be changed later), I want to add a feature that allows them to learn a cantrip of their choice from a limited list. How do I do this? I know how to add cantrips to Feats, but I don't want someone to learn all 6 Cantrips when picking the Feat. I want them to be able to choose which of the 6 Cantrips they should learn while they have the Feat. In my Feat, I tried adding an Option, and to that Option, I tried adding Spells. However no Spells came up in the "Spell Name" bar. It was as if it was asking me to input a custom spell. 

Is what I'm trying to do possible? Is there an easier way to do it? Do I have the right idea, but am simply doing something wrong?

Worst case scenario, I will simply create a Feat for every single Cantrip I want available, and have them select a Feat rather than a Feat that gives them Cantrip options, however, this would mean creating well over 30 Feats! I'd rather not do that, as I feel like that would be a nightmare to share with the community, if they would even allow me to post Feats that simply let you learn an individual Cantrip and nothing more. 

Where you add the spell, if you add all 6 cantrips in the same field it will give them a choice of 1 out of those 6.

Thank you so much for the help!

Happy to, as usual.