I am also traveling to Brussels after Paris on November 27th and there are 3 of us. What I have found out is the hotels during the week are expensive since there is a lot of Business traffic but starting on Friday and Saturday, the rates at the hotels drop at places that can accommodate 3 or 4.
I have booked at the Renaissance Marriott for 3(one bed is a rollaway with an extra charge) but a great rate so don't know if they can do 4 but the rates are so good, you could get 2 rooms.
If you have booked, I would be very interested to see what you have found.
I am having an issue finding a good value for Monday thru Thursday so anything you can share would be wonderful. We found the Saint Nicholas hotel for November 27th and it can handle 3 or 4 but I see mixed review on tripadvisor.
The 70th anniversary of the Battle of the Bulge is happening this year so I am trying to find somewhere close to the tour sites and have explored Luxembourg and can't find anything reasonable for 3 of us. So any other places you have found please let me know. I have been to Ghent and Bruges and those are lovely places to go as is Brussels.