gns3 Topology without switches

Dear All,

I want to build GNS3 INE topology without using using any switches except using for interconnections via vlans for example one switch connecting all routers using dot1.q connections.

and i will use rack rentals for switching features.

my question is that if i use above approach then if i am using foundation labs for each technologies then i can practice switching independentaly using rack rentals

but if i need to start full lengths labs like vol.2 or 3 for v4 labs then how can i complete L3 tasks first and then use rack rentals to complete switching questions?

I hope my question is clear to all but if not please let me know

thanks and regards

Sourabh