Currently, you cannot delegate subnet level persmissions.
However, you can configure role based users. For example, you can give your desktop team Read-Only access so they can see all subnets but not modify anything. The available roles are: Read-Only, Operator, Power User, Administrator, and Default. You can find more detailed information in the Admin Guide:
This is a feature we would very much like to implement in a future release. We get many, many requests for this. We are definitely tracking this as a feature request. Thanks!
I would love to see this across all the Orion Modules. I know I can limit the view of the devices listed via IP / mask, but would love to do that everywhere.
It is now feature of IPAM 3.0