String replace with multiple value result.

Hi,

I have a scenario with a random string test;

"Häradålderön" which my goal is to se the result to "Haradalderon".

Basically replace any [ä, å, ö] with [a, a, o] letter.

I guess using regular expression could do it, but I find it tricky since it might be three sequences to search for ä, å, ö. Any ideas appreciated!