Where can I host 20 children in Brussels?

I have a connection to this traveling school from Korea
Usually it's Protected content aged between Protected content old traveling the world for one year.
They are looking for a place to stay and having a possibility to cook over 2 to 3 weeks period time in Brussels.

I can't really come with any idea but youth hostel or some kind of cultural center where they have accommodation...
any suggestion?
any contact of such cultural center? if you know any?

Thank you for your tips!