An example of how you could map teams to many workspaces using the Terraform Enterprise provider

teams-to-workspaces.tf

# Start w/ a data source to get a list of all the workspaces
# See: https://www.terraform.io/docs/providers/tfe/d/workspace_ids.html
data "tfe_workspace_ids" "all-workspaces" {
  names        = ["*"]
  organization = "my-org-name"
}

# Look up the ID of the teamn you're looking to map
# See: https://www.terraform.io/docs/providers/tfe/d/team.html
data "tfe_team" "architects" {
  name         = "my-architects-team"
  organization = "my-org-name"
}

# Use the new resource for_each support to map out the team permissions
# See: https://www.terraform.io/docs/providers/tfe/r/team_access.html
# And: https://www.terraform.io/docs/configuration/resources.html#for_each-multiple-resource-instances-defined-by-a-map-or-set-of-strings
resource "tfe_team_access" "architects-team-gets-read-permission-on-all-workspaces" {
  for_each = data.tfe_workspace_ids.all-workspaces.ids
  
  access       = "read"
  team_id      = data.tfe_team.architects.id
  workspace_id = each.value
}