Are three people allowed to share a Two-Bed Luxury Sleeper on trains from Hong Kong to Beijing?

We want to book a LUXURY sleeper cabin as it has a private toilet, but we are three people. If i buy THREE adult tickets for a LUXURY sleeper train from HK to Beijing, will my 13 year old daughter, husband and I be able to share a LUXURY sleeper train even though it has only TWO beds (my daughter and I will share a bed)?