One easy way to start finding people is see if you have a standard corporate directory. If you do (and it includes an org chart or titles) you may be able to drill through and try to ID people to talk to. Talking to folks in Mechanical Engineering is always a decent place to start because you can say “Hi I do design, where do you get your designs from?” and they’ll either say “Consultants” or “Talk to Bob, he’s our head of design”. For things like that it’s fine for a cold call or email. VP’s probably won’t be bothered but if you have a good relationship with your VP’s you can ask them to help you find out as well.
In our case, there were central teams within each BU, and then individuals who tackled specific sub-businesses.
Sometimes you stumble upon people by accident or find out that someone was hiding a designer in a closet and didn’t want to share them.