I don't think Stealth Rock/Spikes/etc. is really useful in 3 v 3. Yes, it kills Focus Sashers, but so does Sanstream/Fake Out/Knock Off, which have the respective benefits of not taking up an attack slot, dealing decent damage to low defense Pokemon like Alakazam, and being able to get rid of annoying hax items. Stealth Rock has its own benefits as well, one being that you only need to use it once to disable a Focus Sasher, but it's not as an effective technique IMHO.
For one, to use it to its fullest extent, you will have to take up another moveslot on another Pokemon for Roar/Whirlwind, and chances are, the opponent is going to have something that can deal decent damage over time to your pseudohazer of choice, even if the p-hazer has a recovery move. Not to mention that a Roar lets an opponent receive a free Double Team in some cases, maybe more if Roar misses.
If you're not going to go with that route, and you're just really scared of Focus Sash, then I'd use Fake Out on another Pokemon and replace Stealth Rock with Gyro Ball to hit Ghosts who have Focus Sash. If you're scared about Fake Out missing, I'd use Sandstream; you're guaranteed to have two immunities on your team anyway. Maybe it's just me, but I feel that Stealth Rock isn't as great a technique in 3 v 3 as it is in 6 v 6. Stealth Rock does its job pretty well in getting rid of the Focus Sash, but it just really seems like a waste of a moveslot.
I'd put another move over it on the set, perhaps something to hit Ghosts/Steels/Rocks who resist/are immune to Explosion. Gyro Ball would kill things like Gengar, as stated above, along with Rock Types Zap Cannon hits Skarmory (and the occasional Damp Golduck), and Earthquake gets rid of the trapping Magnezone and Heatran, though you shouldn't really try your luck with the latter. Just my two cents.