Currently, the title of the classification label in Finnish reads as "Tarkoitettu tietynlaiselle yleisölle" which translates as "Intended for a certain kind of audience". I'd propose using the translation "Tarkoitettu rajoitetuille yleisöille" which translates back into English as "Intended for limited audiences." There is a difference of tone and meaning, but most importantly the plural form of the original "Intended for certain audiences" is conserved.