Incoming Analyst -- Strategizing Group Placement?

HI all, I am starting full time at a MM in NYC this July. I would like to know how I can best position myself for placement in my choice group(s), M&A or healthcare coverage (I have a background in science). I received my offer during last fall's full time recruiting on campus, after interning in the summer at a top BB in a non-IBD group.

The problem: I hit it off great during the FT superday with my interviewers but haven't really kept in touch, and I feel like I don't have any goodwill with the bank because I didn't intern there. This may result in me just being thrown into any group.

I am in the process of starting onboarding and would like to know:

A) Whether it is appropriate to reach out to senior level guys in my choice groups (M&A / Healthcare coverage) to grab a coffee / hop on the phone. How could I let it be known I want to land in their group? Should I subtly endear myself to them or subtly suggest my interest?

B) Is it too late--is the rest of the Analyst cohort from the summer already placed, leaving my placement up to chance, or is the whole cohort placed into groups after training?

C) Any other useful advice about the nuances of group placement would be very helpful, thanks.