If I’ve understood your problem, then I think there is a way to achieve it:
- Use a max formula to find the latest start date (as you’ve described)
- Use a formula in the position (or place name) type to check if its start date = person’s max start date (returns a boolean with the name ‘Current’)
- Use a formula in the person type which is
positions.filter(Current = true)
This should return a single position (assuming there is always only one with the highest start date)