Networking for IB intern group placement with no connections

Hello!

I have an offer from a Mid-BB and am starting my attempts to network into a group I am interested in. The issue is I attend a non-target and most groups at the bank have 0 alumni. There is a group with high representation from my school, but I am not interested in the industry they cover.

I am most interested in power, industrials, or comms.

These groups happen to be ranked pretty high and seem harder to be placed into. Is reaching out to random people in these groups weird? I would ask the alum in the group for advice but I'm scared that would potentially burn bridges.

Also, do previous summer internships help with group placement? Last summer I interned at an F500 telecom company.

Thanks!