Attempting to create a formula for work that contains specific criteria for the day-to-day

Hello All,

First post, but been reading a lot of threads in the past years to get help on certain functions and how to use them properly. I have a formula that I'm trying to create but am unable to link it correctly with all the formulas I am aware of.

Here is the issue. For a day to day schedule, the day starts at 0500 and ends at 1500 (3:00 PM). In my work there are many several steps in the process, some short and some long. My end goal is this:

An employee puts the Start time of the process to begin. This start time can be anytime between 0500 - 1500, the employee selects the Step they are starting at (from a drop menu), and the Sum of the times of the steps plus the Starting time will generate an end time before or at 1500 which will be displayed as the last step possible from the list A-Z.

For example: The day begins at 0500, but I begin STEP F at 1045. I would be able to get to STEP H before my shift was complete.

If this seems possible, this would be sooooooooooooooo helpful.

I thank anyone and everyone who has any input. This may seem so easy to the experts, but the time addition with the end time constraint is what is making it difficult for me.

Thank y'all!

**please excuse the fact that I typed 1130 in the start time. It should be 1045.