It can be done, although it is more difficult. Most of the times you only have 2 or three out of 15 people constantly backstabbing and really racking up kills quickly. If you keep these guys busy and engage them in fights where they can't apply this tactic, you will find out pretty quick that they don't have much else in their bag of tricks.
Usually I do it like this:
I check into a server and take a look at the scores. If the first five players have somewhat equal points, then there is a fair chance of having a nice gameplay on this server.
If you have a number one on the server with 25 kills and the next around 7 its a sure sign that there is one backstab whore at work. Seek him out and keep him busy. Most of the time it does the trick.
Sometimes I even do not bother about being number one on the server anymore. If I can have some nice 1v1 duels scoring 10 kills in 20 minutes thats more fun than getting 30 kills in the same time by just pull/backstabbing.