Multiple DirectoryIndex (for different alias domains in the directory) in htaccess maybe?

Question

linux

Essence, in one directory there are several domains, aliases.
Each should be given a separate index file.
This is real?
This is how something does not work, only the first one works:

RewriteCond %{HTTP_HOST} ^domen1\.ru$ [NC] 
DirectoryIndex 1.html
RewriteCond %{HTTP_HOST} ^domen2\.ru$ [NC] 
DirectoryIndex 2.html