While i don’t see a reason to hide groups, i have to ask… Does seeing it really matter?
You still have to face them either way. Odds are you’re not going to play any differently if you know they are stacked. People don’t have to be grouped to play well together.
The only possible thing seeing a group will do is demoralize or tilt your team, if you let it.
That being said, groups should try to be matched against groups, though that will increase que times.