Marking the latest date in a set with duplicates in a column

Hi everyone! I've been banging my head against the wall trying to find a solution for this problem.

I have a dataset with prospects and stages.

I would like to have a marker on whether to include a row in the dataset based on an input date, but the issue is that several prospects have several dates and stages.

I've attached a doc that shows the types of data and where I'd like to have a binary output, with two examples and an edge case where there are duplicate dates. In this file, the rightmost column of each example shows which row should be returning a 0 or a 1, based on different dates entered above.

I would love, love, love any possible help.