IAMAccount.template

{
    "AWSTemplateFormatVersion": "2010-09-09",
    "Description": "Provisions the IAM Account with the groups, policies, and roles needed.",
    "Parameters" : {
        "IAMUser" : {
          "Type" : "String",
          "Default" : "IAMUser",
          "Description" : "Add one IAM user to admin group."
        },
        "ManagedAccount" : {
            "Type" : "String",
            "Default" : "111111111111",
            "Description" : "Define One Managed Account number."
          },
        "Prefix" : {
            "Type" : "String",
            "Default" : "mac",
            "Description" : "Enter the prefix for the service role."
          }
    },
    "Resources": {
        "MacGroup": {
            "Type": "AWS::IAM::Group",
            "Properties": {
                "GroupName": {
                    "Fn::Join": [
                      "-", [
                        {
                          "Ref": "Prefix"
                        },
                        "admins"
                      ]
                    ]
                  },
                "Path": "/",
                "Policies" : [ {
                    "PolicyName": {
                        "Fn::Join": [
                          "-", [
                            {
                              "Ref": "Prefix"
                            },
                            "assumerole"
                          ]
                        ]
                      },
                    "PolicyDocument" : {
                        "Version": "2012-10-17",
                        "Statement": [
                          {
                            "Sid": "VisualEditor0",
                            "Effect": "Allow",
                            "Action": "sts:AssumeRole",
                            "Resource": [
                                "Fn::Join" : [ ":", [ "arn", "aws", "iam","", "Ref": "ManagedAccount","Fn::Join" : [ "/", [ "role", "Fn::Join" : [ "-", [ "Ref": "Prefix","service"] ]] ]] ]
                            ]
                          }
                        ] }
                 } ]
            }
        },
        "addUserToGroup" : {
            "Type" : "AWS::IAM::UserToGroupAddition",
            "Properties" : {
               "GroupName" : {
                "Fn::Join": [
                    "", [
                      {
                        "Ref": "Prefix"
                      },
                      "-admins"
                    ]
                  ]
               },
               "Users" : [ "Ref": "IAMUser" ]
            },
            "DependsOn" : "MacGroup"
         }
    }
}