It appears as though you can connect a Raven directly to the GS2 via the serial communication, which should allow all devices to work together as you want.

The following is taken from GS2 Display—Basic Applications OPERATOR’S MANUAL

Recording Source
The following controllers can be used with AUTO to
automatically communicate when system should turn
recording on/off:
• John Deere Harvest Monitor
• John Deere SeedStar for Air Carts
• John Deere SeedStar Gen 2 Monitor or Variable Rate
Drive for Planters
• John Deere SprayStar Gen 4
• Raven 440, 450, 460, 660
• SideKick
• GreenSeeker
• Rawson Accu-Rate and Accu-Plant
• New Leader Mark III Mark IV
• Dickey-john Seed Manager
• Vanguard PIC Seed Monitor
• Task controller compliant implements (sprayer, seeder
and planter)