Informational Interviews With Other Groups Question

I will be networking this summer to get ready for FT recruiting this Fall.

I don't have a lot of alumni to network with that work in the groups I am most interested in-IB, Capital Markets, ER. I do, however, have some people I could reach out to that are in different departments. My question is should I ask for an informational interview from these people or simply ask them for a referral for an informational interview with someone in another group.

If I ask someone for an Info. Interview and they like me it would be good because they could pass my info along and say "this kid seems interested, determined etc." But, I could also see the possibility of an alum not being happy when I use their time to discuss their career with me and then at the end I (basically) say...well I have no interest in (whatever they do) but can you please connect me with someone in the DCM group?

If I ask an alum accountant at a BB to help me get an info. interview with someone in IBD are they even more likely to ignore because I have no interest in their career & have created no relationship with them?

My current thought process is:
if the person is closely related to these fields maybe I should go for creating the relationship with them first-instead of asking for a connection right away.
(and then...) if the person is NOT closely related (ex: accounting) just ask for a connection that may get me an info. interview.

What do you guys think?