Assistance with Looping through information

Hi All,

I have the following code in a module which is called as part of a longer process:

variable cloud_account {}
variable zoneInfo {}

# Create each specified project
resource "vra_project" "this" {
  
  for_each = { for proj in var.cloud_account.projects : proj.name => proj }
  name = each.value.name
  description = each.value.description
   
  machine_naming_template = each.value.machine_naming_template
  zone_assignments {
    zone_id       = var.zoneInfo.id
    priority      = 1
    max_instances = 0
  }
}

The input for this is as follows (cut from a larger input file)

projects = [
            {
                name = "Development",
                description = "Development project"
                administrator_users = {email="Administrator@automationpro.lan"},
                machine_naming_template = "dev-$${resource.name}-$${####}",
            },
            {
                name = "Staging",
                description = "Staging project"
                machine_naming_template = "stg-$${resource.name}-$${####}",
            },
            {
                name = "Production",
                description = "Production project"
                machine_naming_template = "prd-$${resource.name}-$${####}",
            },
            {
                name = "DR",
                description = "DR project"
                machine_naming_template = "dr-$${resource.name}-$${####}",
            }
        ],

What I am trying to achieve is to loop through each project and create which is working fine. However, I am not sure how to deal with the administrator_users? There could be 1,2,10, any number of them defined for each project, so in my mind, I am thinking a loop within a loop which I believe is not possible.

The roles are added as per the following, and repeated for each (full example here)

administrator_roles {
    email = "jason@vra.local"
    type = "user"
  }

Any advice on how I should go about this?
For reference this is working with the vRA Provider (if that matters) found here

Thanks for any and all help in advance.