You can configure the bandwidth management for every VM. With Hyper-V Manager, choose a VM, right-click and select settings. Choose then the network adapter, and check the checkbox Enable bandwidth management. Then you can specify the Minimum and Maximum bandwidth.
With PowerShell, you use set-vmnetworkadapter with the –MinimumBandwidthWeight parameter. It takes value from 0 to 100. 0 disables it.
set-vmnetworkadapter -vmname vm2 -name "Network Adapter" -minimumBandwitdhweight 50