Load defined index from subfolders, .htaccess

I have https://some.ru/sub/index.php And several folders in sub like

/sub/sub1/, /sub/sub1/sub1-1/, /sub/sub2/, /sub/sub2/sub2-1/sub-2-1/

What lines i need to add in .htaccess to get sub/index.php load when i try to load one of these folders? without url redirection

thanks