R1Hopeful
From what I've seen so far, yes they do. We've only seen Deloitte here on campus so far because it's fairly early, however there were a few people from the Digital Strategy practice here. I believe each firm structures this group a little differently, but from what I saw at Deloitte the digital strategy group is under the S&O practice, but digital in general is seen as a core competency that can span multiple practices. Regardless, they stated that they do recruiting for all of their practices at the same time. You'll just have to state your interest as you go through recruiting and they'll try to connect you with people in their digital strategy group.
As for PWC and BCG, I suspect they do something similar and that they'll recruit broadly when they come to your school. But if you're extremely interested in digital strategy specifically, you just have to let them know and they'll make sure you get staffed on those types of projects if you get the job