Combine cells when column match

It could be done with Power Query

In brief:

- query source table and merge Item Number and Model columns with separator which is definitely not in names of both;

- reference that query and group new column selecting min Year as output;

- same for max Year;

- merge above two queries and split merged Item Number & Model column;

- create new column as Model minYear-MaxYear;

- group on Item Number without aggregation of other columns;

- from resulting tables in each grouped row extract first column of such table as list;

- expand list as values with ", " separator.

Rest is cosmetic, please see attached