Hello Sims!
The network topology that you are describing would not COMPLETELY simulate the frame relay situation in this lesson. What you are describing would require all communication between R1 and R3 to go through R2 just like in the lesson, however, this also means that the two interfaces on R2 that connect R1 and R3 would have to be on the same subnet, something that is not possible. So you would just be creating two point to point links on different subnets, however, in the frame relay example in the lesson, all three routers are in the same subnet.
What you require is to create a frame relay switch on GNS3. You can find some frame relay examples in GNS3 from Rene’s GNS3 Vault here: http://gns3vault.com/labs/frame-relay/
I hope this has been helpful!
Laz