Allright... here is the scenario. We are using Financial Services Cloud. It kind behaves like Person Accounts, without having Person Account really enabled for the org.

FSC has the concept of an Individual. There are some components (part of the FSC package) that will show details (on the Account) that come from the Contact related to the Account.

Whenever you create an Individual, it also creates a Contact with the same name and populate a field called PrimaryContact with the Contact ID related to that Account. This way you can show fields from the Contact on the Account page layout (like email, phone, mailing address, etc).

There is one Lightning component that comes with the FSC called "Client Related List". This component will show all the related lists for the Account, as well all the related lists from the Contact linked to the Account. The related lists shown within this components are the relates lists selected within the Account and Contact standard page layouts.

Unfortunately we can't remove the Account Relates lists from this component (since is part of a package).

Question is: How hard would be to create a custom component to show just one, or multiple, related list(s) on the Account Page layout, where the related lists will be driven from a Lookup field (from Contact)? Basically I want to select specific related lists from Contact in the Account page Layout) without been attached to the standard Contact page layout.

Any links to documentations, samples, etc?

Thanks.