Hi Rena,
Unfortunately not as far as I can tell in either v8.20 or the new v9.0. This is one of those frustrating things that has been supported in vCenter 5.x and 6.x for ages but isn't exposed in the vCloud Director interface or API.
You can use Independent disks and move these between VMs in vCloud Director 8.20 (and 9.0) using the API - I wrote a PowerShell module for this and a blog post: https://kiwicloud.ninja/2017/02/using-independent-disks-in-vcloud/ to make it easier to create/attach/detach/delete independent disks from vCloud VMs, but there is currently no way that I am aware of to set the bus-sharing that would need to be present to allow the same disk to simultaneously be attached to multiple VMs.
This is one of a number of vSphere features that really should be added in vCloud Director - others include UEFI BIOS selection, configuration of VM video RAM to support better console resolutions and several others imho. I've submitted feedback to VMware on many of these and hopefully they'll get added at some point.
If you need to do this for Microsoft Clustering (the usual case for bus-shared disks attached to multiple VMs), there is a supported workaround using in-guest mounted iSCSI disks, but that relies on having highly available/redundant iSCSI storage available.
Regards, Jon.
