I'm not sure how you can do that -
What I would do - to get the job done.....
Dump (export) the "posts" table then create a new table "posts2" or something.
Import the posts into the new table - Then delete everything that's not that keyword
DELETE FROM w3t_Posts2
WHERE B_Board != 'AccessoriesArticles'
Then dump the "posts2" table - and there you have just the forum you want.
NOW - This is important - You can't import it elsewhere if the post numbers (B_Number) will cross over the existing database. And the post numbers in your export can not be changed, because eeach reply is tied to the thread by number, as well as the post it's in reply to.
Now if the highest number in your new database is 5000. And your export uses 10000-15000 you could safely import them. But then since that number increments each post - I *think* you'd have to set the nex tnumber higher than what you imported, so that the post numbers never cross.
So in certain situations it's doable - but be careful.
It would be easy to get the post number mixed up and then nothing would be right.
Backup everything first.