The mistake you made was allowing them entry to put their luggage down if you did not want it there. You could say "No, I only allow registered guests to enter my apartment. I can't accommodate any one else's luggage. Sorry. "
Once they entered, it is a bit harsh not to let them use the bathroom. So best not to allow them to enter at all if you don't want them using the bathroom.
However, consider traveling in a big group to a foreign country, arriving at your friend's lodging and having to pee. But the proprietor of the lodging says you can't use the bathroom. Ouch.
Also consider having to lug your luggage around all day because your friends can check in now but you can't check in until hours later or on the other side of town.
You could have politely but firmly said "Only the registered guests can come in. They can bring the luggage in and out but they need to put it only in the room they reserved. The rest of you need to wait outside."
Why not communicate with the registered guests and say you are startled by the appearance of this large group and you would like to be friendly and helpful but you are going to ask them to have their friends wait outside while the registered guests organize the luggage in their room and that the registered guests can ferry the bags back out later.
By the way, it is a bit inappropriate to mention the nationality of the guests in a perjorative manner. Better to call them people, tourists, friends than to mention their nationality in that way.