2 drop down lists that are dependent on one another with vlookup

[STEVEMILLS04]

Hey there. My goal is to have two drop down lists that depend on each other. List A is names and list B is job title. If the user selects a job title in list B, list A should only show those names with that job title. This is easy. The confusing part for me: If the user instead selects a name in List A, list B should then complete a vlookup based on list A. To add to the mass confusion, but not a necessity, if one of the fields are changed, the other list should update.

List A is column G and list B is column H. I truly appreciate any help that can be provided