Categories and Tags at a Gallery Level

Site URL: https://www.mushaventures.com/

I would like to organize my galleries on my page by giving each one a 'tag' or 'category'. The ideal situation is I can define a few parent and child categories and then allow filtering by different items on my page. 

I would like to add the following categories:

1. Country (and then define the country by investment)
2. Status (Active, Exited)

This will allow people who visit my site to be able to see groups of categories more easily - which I am sure would be useful in LOTS more cases (shopping, photography etc).

Please can someone teach me how to do this, or can we get this feature added!

Maybe useful https://support.squarespace.com/hc/en-us/articles/209114107-Organizing-Gallery-Pages