data "github_team_sync_groups" "my_groups" {}

resource "github_team" "some_team" {
  name        = "SomeTeam"
  description = "Some cool team"
}

resource "github_team_sync_group_mapping" "team_mapping" {
  team_id  = github_team.some_team.id
  
  dynamic "group" {
    for_each = [for g in data.my_groups.groups : g if g.name == "some_team_group"]
    content {
      group_id          = each.value.group_id
      group_name        = each.value.group_name
      group_description = each.value.group_description
    }
  } 
}