Implement Rule for "Five Form Irish"

The header entry would be:

Plural-Forms: nplurals=5; \
    plural=(n==1) ? 0 : (n>=2 && n<=4) ? 1 : 2;(n==1 ? 0 : n==2 ? 1 : n>=3 && n<=6 ? 2 : n>=7 && n<=10 ? 3 : 4)

Source: PoEdit