Ok, i found solution for this
And its to enable "use site specific assets"
Se this post from Mathias is you have troube whosing them.
Episerver Find will not display other sites documents by default.
and above works if you have languages as multisites, one site/node per language
If you handle languages in one node by translating (how langugages usually are handled in episerver) , my solution willnot work and you will have to go on with https://gregwiechec.com/2015/07/localizable-media-assets/
So question still remains how to exclude them from find :), guess is a question to Episerver
By default assets are not localized by episerver but there is a way of doin it and it can be found here :):
however, how do we adjust the search to exclude not translated documents from the search result?