No but if you find out how they do it please let me know
Jokes aside,
You sign up to be an ATCO, you can make a personal preference known to the relevant people (just as with postings), but you've signed up to do whatever you're assigned to do. If you're not ready to commit to that then there are a lot of other people who are.
It's very harsh, but that's the way it works. I got what I wanted to do, some on my course did not. Down both routes though is a very good job if you make it through so I wouldn't worry too much about it.
Also the preferences vary, in my experience most people aren't that bothered. On some courses most want Aerodrome, on some most want Area, so it varies.