Thanks for your response.
I can see were user1 shouldn't be able to see the files of user2 but user1 not being able to see his own files is most certainly odd in my book. Any clue why this is? (trying to understand)
I see that I've had a typo in the question, we have got the folowing filepaths, within linux the filepaths for the homedirs are exactly the same:
fptmaster should have access to /home/ftpmaster and all subdirectorys with read/write
user1 should have access to /home/ftpmaster/user1 and all subdirectorys with read/write
user2 should have access to /home/ftpmaster/user2 and all subdirectorys with read/write
user3 should have access to /home/ftpmaster/user3 and all subdirectorys with read/write
ftpmaster should not be able to list /home, because he must be jailed within his homedirectory.
user1, user2 and user3 should not be able to list /home/ftpmaster, because they must be jailed within their homedirectory.
Maybe this explains the situation