Tanveer thanks for responding.
The plugin won’t work. I think it will create an endless loop.
The .htaccess example doesn’t cover a situation close enough to mine for me to be able to figure out what to do.
My guess is that it has to be fixed in the .htaccess file and that I will have to modify the code between <IfModule mod_rewrite.c> and </IfModule>. I think WP ignores everything outside the module.