If you want different virtual machine with different VLANs on one host, follow these steps:
1. the port that real NIC (physical nic) is connect must be "trunk".
2. if u have a VM with 172.20.1.15 and the other is 172.20.4.20 and want both of them with one NIC and one port, u have two ways:
first: to choose VLAN ID to "ALL (4095)"
second: to create different Virtual switches which connect to one and set the vlan for each of one.
these two solutions depend on the networking view, I mean the base of the Network+ and managing the network etc, broadcasting.
Saman Salehi