Graphviz：我找不到使用Graphviz来堆叠集群的方法

Question

我正在使用Graphviz设计技术/业务架构。

遗憾的是，我无法复制以下图片（信用：https://www.celent.com/insights/910618694）

以下是使用Graphviz的以下源代码的结果

我尝试了几种解决方案：

1. 堆积子图
2. 将主要项目（即Presentation_layer）与隐藏节点链接起来
3. 等

我看了很多关于stackoverflow或其他地方的帖子，但找不到有关该主题的任何信息。

有什么想法应对挑战吗？

这是完整的源代码

.. graphviz::

# insipried by https://www.celent.com/insights/910618694
# graphviz samples : https://renenyffenegger.ch/notes/tools/Graphviz/examples/index

digraph digitization_insurance {

    {
        node [shape=plaintext, fontsize=16, rankdir=LR];

        # PRESENTATION
        Presentation_layer [shape=house, sides=5, label="Presentation\nlayer"]
        Robo_advisor [label="Robo advisor"]
        Broker_portal [label="Broker portal"]
        Customer_portal [label="Customer portal"]
        Call_centre [label="Call center"]
        Middle_office_work_station [label="Middle office work"]
        Back_office_workstation [label="Back office workstation"]

        # BUSINES LOGIC
        Business_Logic_Tier [label="Business\nLogic Tier", shape=house, sides=5]
        API_Gateway [label="API Gateway"]
        BPM [label="Business\nProcess\nModeling"]
        BRM [label="Business\nRule\nManagement"]

        Quote [label="Quote"]
        Entreprise_services [label="Enterprises\nservices"]; 

        # DATA
        Data_Tier [label="Data Tier", shape=house, sides=5]
        Claims [label="Claims"]
        Policy [label="Policy"]
        Underwriting [label="Underwriting"]
        Bill_Collect [label="Bill collect"]
        CRM [Label="Customer\nRelationship\nManagement"]
        CDI [label="Customer\nData\nIntegration"]
        Data_warehouse [label="Data Warehouse"]

        Physical_Tier [label="Physical\nTier", shape=house, sides=5]

        Presentation_layer -> Business_Logic_Tier -> Data_Tier -> Physical_Tier [dir=none]

        subgraph cluster_Presentation_layer {
            share=record
            Presentation_layer 
            subgraph cluster_Presentation_layer_0 {
                subgraph cluster_Presentation_layer_1 {
                    label="cluster Presentation layer 1";
                    rankdir=LR; 
                    rank=same;
                    style=dotted;
                    Telephone; Robo_advisor; Mobile; SMS; Browser; Chatbots;
                };

                subgraph cluster_Presentation_layer_2 {
                    label="cluster Presentation layer 2";
                    rankdir=LR; 
                    rank=same;
                    style=dotted;
                    Broker_portal; Customer_portal; Call_centre; Middle_office_work_station; Back_office_workstation;
                };
            };
        };

        subgraph cluster_Business_Logic_Tier {
            Business_Logic_Tier

            subgraph cluster_Business_Logic_Tier_1 {
                label="cluster Business logic tier 1";
                rank=same;
                style=dotted;
                API_Gateway;
            };

            subgraph cluster_Business_Logic_Tier_2 {
                label="cluster Business logic tier 2";
                rank=same;
                style=dotted;
                BPM; BRM;
            };

            subgraph cluster_Business_Logic_Tier_3 {
                label="cluster Business logic tier 3";
                rank=same;
                style=dotted;
                Policy_and_product_management; Claims_management, Customer_management; Finance_management; 
            };

            subgraph cluster_Business_Logic_Tier_4 {
                label="cluster Business logic tier 4";
                rank=same;
                style=dotted;
                Quote; Policy; Products; Claims; Customers; Entreprise_services; 
            };
        };

        subgraph cluster_Data_Tier {
            Data_Tier
            subgraph cluster_Data_Tier_1 {
                label="cluster Data tier";
                rank=same;
                style=dotted;
                Claims; Policy; Underwriting; Bill_Collect; CRM; CDI; Data_warehouse;
            };
        };

        subgraph cluster_Physical_Tier {
            Physical_Tier
            subgraph cluster_Physical_Tier1 {
                label="cluster Physical tier";
                rank=same;
                style=dotted;
                Servers; Data_storage; Data_centers;
            };
        };

        label="Digitization of the Insurance industry v2019-09-12";
    }
}