Edit "Role Type Id" list

[Bertuzzi, Armando [Nervianoms]]

Hi all,
what relationship exists between field "Role Type Id" found in form
"Project > Resources > Add a Resource" and fields "Role Type" and "Type"
found in form "Party  >  Parties"?
How is it possible to add new items to the "Role Type Id" list?
Many thanks in advance for your help,
Armando