Many of the veterans of World War I also fought in the Spanish American War.  The State of Indiana published the book: Record of Indiana Volunteers in the Spanish American War 1898-1899. in 1900.

The complete book is available online from the Library of Congress: https://www.loc.gov/item/01005459/

Google Books also offers it for free to download:  https://www.google.com/books/edition/Record_of_Indiana_Volunteers_in_the_Span/JnYtAAAAYAAJ?hl=en 

The veterans listed in the book are listed here in a searchable database.

This list includes every Indiana volunteer veteran that fought in the four Infantry regiments, two light artillery batteries, one Company of Engineers, and one Company for the Signal Corps that were requested by President William McKinley.