What would be the best way to build a one to many relationship in my provider?

Hello, I have a provider where I define all my data that will be used in my app. The data comes from the backend in protobuf messages. I am going to be receiving a protobuf message similar to this

message Waypoint { double xPos = 1; double yPos = 2; } message Mission { string id = 1; repeated Waypoint waypoints = 2; }

And I’m unsure how to structure this in my provider. I was thinking of doing it this way

waypoint: { missionId: number yPos: number xPos: number }[] mission: { id: number }[]

But wanted to check to see if there is a better, more organised way do this, any advice?