Creating a network diagram that consists of 3 Debian VMs

Hello, I am currently using VirtualBox to create a 3 VM network where The first VM and second VM are supposed to act as routers for the third VM in a daisy chain topology. The catch is that the middle VM (VM2) is not supposed to be able to access the internet while the two end VMs (VM1 and VM3) should be able to. The first VM is supposed to have a NAT interface and a LAN interface, the second VM is supposed to have 2 LAN interfaces and the third is supposed to have only one LAN interface. I have already created the network but I don't know how to prevent VM2 from having internet connection while still allowing VM3 to pass through the internet and still be able to ping VM1. If you have any suggestions please help me out :)