Switching from product to coverage before FT starts - who should I talk to and who should I avoid talking to?

Just to give a little background: I am currently a senior heading into FT this summer. The offer is at a non-BB that is debt-heavy (Wells/Mizuho/etc). I summered in a product group and while I liked it quite a lot, I do want to get a better exit to PE so the plan is to try switching to an M&A/coverage group first and then lateraling to a BB.

If I were to try networking internally before my FT starts to see if I can move into coverage, who is usually the best contact to start with? And perhaps more importantly, who should I be mindful of not informing too soon? I built quite a close connection with an MD in another product group (also an alum) that I wanted to reach out to see if he has any touchpoints in the coverage groups, but just a little worried that my old group will find out (I am assuming I should try to not let any of my original group find out about the switch too early).

So, should I talk with HR/coverage contacts first or someone else? Thanks a lot.