diff --git a/group_vars/matrix_servers b/group_vars/matrix_servers
index df5b12ebb..d5034917c 100755
--- a/group_vars/matrix_servers
+++ b/group_vars/matrix_servers
@@ -3893,7 +3893,7 @@ matrix_synapse_container_manhole_api_host_bind_port: "{{ (matrix_playbook_servic
 
 matrix_synapse_container_network: "{{ matrix_homeserver_container_network }}"
 
-matrix_synapse_container_additional_networks: |
+matrix_synapse_container_additional_networks_auto: |
   {{
     (
       ([matrix_playbook_reverse_proxyable_services_additional_network] if matrix_synapse_container_labels_traefik_enabled and matrix_playbook_reverse_proxyable_services_additional_network else [])
@@ -4052,7 +4052,7 @@ matrix_synapse_reverse_proxy_companion_enabled: "{{ matrix_synapse_enabled and m
 
 matrix_synapse_reverse_proxy_companion_container_network: "{{ matrix_synapse_container_network }}"
 
-matrix_synapse_reverse_proxy_companion_container_additional_networks: |
+matrix_synapse_reverse_proxy_companion_container_additional_networks_auto: |
   {{
     (
       ([matrix_playbook_reverse_proxyable_services_additional_network] if matrix_synapse_reverse_proxy_companion_container_labels_traefik_enabled and matrix_playbook_reverse_proxyable_services_additional_network else [])
@@ -4585,7 +4585,7 @@ matrix_dendrite_federation_enabled: "{{ matrix_homeserver_federation_enabled }}"
 
 matrix_dendrite_container_network: "{{ matrix_homeserver_container_network }}"
 
-matrix_dendrite_container_additional_networks: |
+matrix_dendrite_container_additional_networks_auto: |
   {{
     (
       ([matrix_playbook_reverse_proxyable_services_additional_network] if matrix_dendrite_container_labels_traefik_enabled and matrix_playbook_reverse_proxyable_services_additional_network else [])
diff --git a/roles/custom/matrix-dendrite/defaults/main.yml b/roles/custom/matrix-dendrite/defaults/main.yml
index d602a860e..a3854315f 100644
--- a/roles/custom/matrix-dendrite/defaults/main.yml
+++ b/roles/custom/matrix-dendrite/defaults/main.yml
@@ -48,7 +48,9 @@ matrix_dendrite_container_network: ""
 # A list of additional container networks that the container would be connected to.
 # The role does not create these networks, so make sure they already exist.
 # Use this to expose this container to another reverse proxy, which runs in a different container network.
-matrix_dendrite_container_additional_networks: []
+matrix_dendrite_container_additional_networks: "{{ matrix_dendrite_container_additional_networks_auto + matrix_dendrite_container_additional_networks_custom }}"
+matrix_dendrite_container_additional_networks_auto: []
+matrix_dendrite_container_additional_networks_custom: []
 
 # Controls whether the matrix-dendrite container exposes the HTTP port (tcp/{{ matrix_dendrite_http_bind_port }} in the container).
 #
diff --git a/roles/custom/matrix-synapse-reverse-proxy-companion/defaults/main.yml b/roles/custom/matrix-synapse-reverse-proxy-companion/defaults/main.yml
index d0638a244..b4ab73b0d 100644
--- a/roles/custom/matrix-synapse-reverse-proxy-companion/defaults/main.yml
+++ b/roles/custom/matrix-synapse-reverse-proxy-companion/defaults/main.yml
@@ -35,7 +35,9 @@ matrix_synapse_reverse_proxy_companion_container_network: ""
 
 # A list of additional container networks that matrix-synapse-reverse-proxy-companion would be connected to.
 # The playbook does not create these networks, so make sure they already exist.
-matrix_synapse_reverse_proxy_companion_container_additional_networks: []
+matrix_synapse_reverse_proxy_companion_container_additional_networks: "{{ matrix_synapse_reverse_proxy_companion_container_additional_networks_auto + matrix_synapse_reverse_proxy_companion_container_additional_networks_custom }}"
+matrix_synapse_reverse_proxy_companion_container_additional_networks_auto: []
+matrix_synapse_reverse_proxy_companion_container_additional_networks_custom: []
 
 # Controls whether the matrix-synapse-reverse-proxy-companion container exposes its HTTP Client-Server API port (tcp/8008 in the container).
 #
diff --git a/roles/custom/matrix-synapse/defaults/main.yml b/roles/custom/matrix-synapse/defaults/main.yml
index 1804d243c..d35fe2e5a 100644
--- a/roles/custom/matrix-synapse/defaults/main.yml
+++ b/roles/custom/matrix-synapse/defaults/main.yml
@@ -132,7 +132,9 @@ matrix_synapse_container_network: ''
 # A list of additional container networks that the container would be connected to.
 # The role does not create these networks, so make sure they already exist.
 # Use this to expose this container to another reverse proxy, which runs in a different container network.
-matrix_synapse_container_additional_networks: []
+matrix_synapse_container_additional_networks: "{{ matrix_synapse_container_additional_networks_auto + matrix_synapse_container_additional_networks_custom }}"
+matrix_synapse_container_additional_networks_auto: []
+matrix_synapse_container_additional_networks_custom: []
 
 # Controls whether the matrix-synapse container exposes the Client/Server API port (tcp/{{ matrix_synapse_container_client_api_port }} in the container).
 #