Are you able to backstab players on Starcraft II?

if you played a Beta, were you able to backstab players like in starcraft 1?

me and my buddy would get on in starcraft 1 right. we would play against each other with other 2 people. so me and another person vs. him and another person. then in like 5 mins we would have 1 of us unally with a person and rush his base nuking him to pieces. then the 3rd guy would just sit there waiting for him demise. it was the funnest thing to do after playing so many regular games.

so my question is, are you able to do this in starcraft ii? or is it like in warcraft 3 where blizzard killed this feature like they killed all the fun in WoW with their lich king crap? if you cant backstab, then *** that game!