Lists of content divided by posts' first letter

Got it! Now I need to reuse code to solve this

My post have this structure
Blondie — Parallel Lines (1978)
Blackstreet — Blackstreet (1994)
Big Black — Songs About Fucking (1987)

I cut year string (substr .Title -2 4) but I need to do sort then as something like
{{ range sort .Site.RegularPages }}{{ substr .Title -2 4 }}
correct?

Output: https://khabaroff.com/1000/page/years/

Here is repo