Ability to add a sublist to a List

It would be great to have the ability to create a sublist under a list and see the items in the parent for a complete picture. Use case example: in my work at a nonprofit we have financial sponsors who provide money through the organization and we turnaround and award the money to multiple community projects. The visual would be:

main list: Sponsor Name

 sublist: Sponsored Project 1 sublist: Sponsored Project 2 sublist: Sponsored Project 3