If the fields are created with Lookup values based on a relationship, when you import records FileMaker asks wheter or not you want to "Perform auto-enter options while importing". If this is checked the values from "all db" should populate your fields A, B, C. However, you can force them to be updated at any time by creating a simple script. First 'go to' the field used as the relationship key, then use the command "Relookup Field Contents". This will refresh any data in A, B, C based on the relationship to "all db"