Help making something like a decision tree with dropdowns

Hello,

I would like help creating a thing please. I'm pretty confident that Excel will be able to handle it, but I'm not sure how do go about it.

I work in a medical practice, and for this one task we have a very complicated assigning structure which I'm wanting to simplify. The task is requested by a Doctor, and is then assigned to a Person to report on based off of who the requesting Doctor is, and what day of the week it is. It could look like any of the following scenarios:

Dr A requests the test on Wednesday, and so it is assigned to Person Z

Dr A requests the test on Tuesday, and so it is assigned to Person Y

Dr B requests the test and it is assigned to Person Y

Dr C requests the test and it is assigned to Person X, except if it's a Tuesday then it's Person Y

Dr D requests the test and it is assigned to Person W, but only once a day, and after that it goes to person Y on a Wednesday, and Person X every other day

This task involves a list of maybe 50 Doctors, and almost as many Person's. I'm hoping to eventually have an Excel form where I can select a day of the week, and a Doctor, and it will tell me who the Person is.  

I hope that that makes sense, and I'm hoping someone might be able to help point me in the right direction please? Thanks