Wherever you are hotlinking from simply add as many domains as you own like this...

PHP Code:
RewriteCond %{HTTP_REFERER} !^http://(www\.)?domain1.com(/)?.*$     [NC]
RewriteCond %{HTTP_REFERER} !^http://(www\.)?domain2.com(/)?.*$     [NC]
RewriteCond %{HTTP_REFERER} !^http://(www\.)?domain3.com(/)?.*$     [NC]
RewriteCond %{HTTP_REFERER} !^http://(www\.)?domain4.com(/)?.*$     [NC] 
Then upload that to domain.com - Where that is the domain you are hotlinking from.

Is that what you mean?

Regards,

Lee