How did you manage to get a return offer from another team as a summer intern?

Incoming IB summer intern at a BB. Was aiming for an industry group but got placed into a team with apparently very few exit opps (Niche, less technical, broad coverage). Most importantly, no headcount, so a return offer from the same team is not possible. If I aim to get an offer from another team, is my relationship with my line manager the most important so he/she would vouch for me, or should I spend more time networking with the team I'm aiming for. Would be grateful if anyone could share your advice if you've been in a similar situation.