How to setup dependent drop down list...?

Greetings Everyone!

I知 looking for some help to be able to automate an alert process for my customers. Usually, I need to send out 25-30 alerts every day. In the past these were almost the same, and I was using the attached solution of Ron. It works brilliantly. However, there have been a lot of changes in our work dynamics because which the process has changed by leaps and bounds. The alert process is the same but the problem is that I now have 35 separate types of them that need to be relayed depending upon the scenario.

What I知 requesting:

Is some help with some customization to this existing superb solution as per the explanation in tab 1 of the attached sheet. Please assist

There is load of data so I would like it be as dynamic and as user friendly as it can be made.

Thank you in advance!