Connectivity between Two Transport Zones in NSX

hi

I have a doubt on Connectivity between Two transport Zones in NSX. As per Transport Zones in VMware documentation

1. There is a 1:1 relation between Logical SWitch and Transport Zones

2. A logical switch cannot be part of Two Transport Zones

3. We cannot attach a DLR or ESG to two transport Zones

4. To acheive Security Isolation, We should map the VM's to a seperate Transport zone so that Other VM's part of other transport zones does not visibility of these VM's.

My understanding we can Interpret a transport zone as a Tenant and achieve a Isoloation. In case if I want to have communication between Vm's in two transport zones how do we achieve. Can some one explain or point me to VMWare documentation on routing between TRansport zones.

regards

vempati