distinguishing multiple words in one cell of excel

I have been volunteering for a local nonprofit, and I was hoping to make an organized list of donors for them. I am not sure if my wish is possible, but I thought I might as well ask the experts.

I have organized my excel sheets with drop down menus for every column (name of organization, country of origin, areas of interest, etc.). In certain columns, like column I labeled "geographic interest," many of the donors compatible with this organization have more than one country of interest. Therefore, many of the cells in column I have more than one country listed within them, separated by commas. In the dropdown menu, however, these countries are all then listed together. For example:

Donor A only funds projects in India, but donor B funds projects in India, Bangladesh, and Uganda. If I select "India" in the drop down menu, only Donor A will show up (because I would have to select "India, Bagladesh, and Uganda" for Donor B to show up).

How can I make it so that the countries of Donor B can be fully distinguished, so that selecting "India" in the drop down will show all options having geographic interest in India (whether or not they also have interest elsewhere)?

Thanks in advanced for any assistance!