How to create messenges showed in specific forum

sois1193

Vanilla has a cool feature that the admin can create their own messages which can be show in categories page, all discussion page. But we cannot defined which messages will show for just only the user which has user id we has setup or specific forum id.
I think it'll be a cool stuff for advertise, fast announce.
Can anybody help or someone has this plugins?
Thanks so much and sorry for my bad english, i'm come from vietnam