Before I left, I heavily considered moving into BCG GAMMA instead of switching to another data analytics company.
When joining, I also heavily considered a path that would lead to BCG Digital Ventures.
Both of the above options were real/tangible - decision-makers in both were asking me to make the leap :)
This is not anything exceptional, it's just networking and having + articulating a vision! In order to do this you need to:
1) Build a strong reputation
2) Show a clear interest, affinity, and (ideally) project experience in that area and
3) Network to know people in the branch in which you're interested.
Happy to answer any further questions about what each specifically does, what the cultures are like, how to position yourself specifically for each one, etc. etc. Just PM me!