Group of Numbers (Question & Bug)

First of all.. when grouping numbers, the output is not “#”, but “0-9”.
It′s okay, but it would be useful to switch from 0-9 to # in the shortcode. I like “#” more ??

Then my question.

In europe, indexing works normally numbers,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z

So first question: How to show “#” or “0-9” as first element?

Then, we have some special characters like “ü”, “?” and “?”.
These can be interpreted like “ü = ue”, “? =oe” and “? = ae”.

Could be useful if you want to make your plugin fit for germany, austria, switzerland and parts of netherlands, belgium, italy, poland…