Here are some articles on creating dependent drop downs
Different Drop Down Lists in Same Excel Cell August 9, 2010 https://contexturesblog.com/archives/2010/08/09...
You can use data validation to create drop down lists in Excel. With a bit of Excel magic, you can create dependent drop down lists, so the selection in one drop down controls what...
Create a Dependent Drop Down List in Excel https://excelchamps.com/blog/dependent-drop-dow...
2017-10-24
A drop down list is an awesome tool. You can pre-define some values and user can enter data by selecting one of those values. One of its advanced features is a “Dependent Drop Down List”. A dependent drop down is all about showing values in a drop down list according to the selection of the value in another drop down.
In the below example, you have two drop-down lists. Size drop down is dependent on product drop down. If you select the white paper in product cell then in size drop down will show small and medium. But, if you select gray paper then its size will be medium and large.
Clear Dependent Drop Down Cells September 11, 2014
https://contexturesblog.com/archives/2014/09/11...
You can use data validation to create a drop down list on an Excel worksheet. For example, show a list of countries, if you click a cell in column B. After you’ve set up that first list, you can make another list, in column C, to show the cities for the selected country.
create cascading drop downs in Excel – video http://chandoo.org/wp/2015/08/31/cascading-drop...
Cascading drop downs enhance usability of your dashboards & interactive workbooks. A cascading drop-down is a 2 or more level selection mechanism. When you have 100s of selection choices, instead of creating one massive drop down or combo-box, you can set up multiple levels of drop downs, so that users can narrow down their selection. For example, users can select Country, State and then City using cascading drop downs.