Yes, all video's uploaded by a user have unique permissions settings to the video. It can be uploaded to a channel and have permissions set. If the group is a 365 group then each group has a Stream location for it with permission open like everything else in 365 groups to all members of that group. So if you upload to a group it will allow that group to access.
If you only want to upload you can do this, and set permissions to "People" then add a security group as a person which will allow access to that group as well.
