diff --git a/models/base.rb b/models/base.rb
index e5ca90b45..641d03582 100644
--- a/models/base.rb
+++ b/models/base.rb
@@ -53,7 +53,7 @@ def self.has_many(name, options = {})
       super
 
       define_method(name) do
-        self[name] || []
+        self[name] ||= []
       end
 
       define_method("#{name}=") do |vals|
diff --git a/models/concerns/expand_data.rb b/models/concerns/expand_data.rb
index 0c7c75edf..3b69f037b 100644
--- a/models/concerns/expand_data.rb
+++ b/models/concerns/expand_data.rb
@@ -45,6 +45,14 @@ def adapt_relations_between_shipments
     }
   end
 
+  def add_relation_references
+    self.relations.each{ |relation|
+      relation.linked_services.each{ |service|
+        service.relations << relation
+      }
+    }
+  end
+
   def add_sticky_vehicle_if_routes_and_partitions
     return if self.preprocessing_partitions.empty?
 
diff --git a/models/relation.rb b/models/relation.rb
index 7ad432c3c..9273bb3e4 100644
--- a/models/relation.rb
+++ b/models/relation.rb
@@ -22,6 +22,7 @@ class Relation < Base
     field :type, default: :same_route
     field :lapse, default: nil
     field :linked_ids, default: []
+    has_many :linked_services, class_name: 'Models::Service'
     field :linked_vehicle_ids, default: []
     field :periodicity, default: 1
 
diff --git a/models/service.rb b/models/service.rb
index 742ed558a..ef145d1d1 100644
--- a/models/service.rb
+++ b/models/service.rb
@@ -56,5 +56,6 @@ class Service < Base
     has_many :activities, class_name: 'Models::Activity'
     has_many :sticky_vehicles, class_name: 'Models::Vehicle'
     has_many :quantities, class_name: 'Models::Quantity'
+    has_many :relations, class_name: 'Models::Relation'
   end
 end
diff --git a/models/vrp.rb b/models/vrp.rb
index 7309ad2e9..959875585 100644
--- a/models/vrp.rb
+++ b/models/vrp.rb
@@ -228,6 +228,7 @@ def self.check_consistency(hash)
     end
 
     def self.expand_data(vrp)
+      vrp.add_relation_references
       vrp.add_sticky_vehicle_if_routes_and_partitions
       vrp.adapt_relations_between_shipments
       vrp.expand_unavailable_days
@@ -325,6 +326,7 @@ def self.filter(hash)
 
       self.remove_unecessary_units(hash)
       self.generate_schedule_indices_from_date(hash)
+      self.generate_linked_service_ids_for_relations(hash)
     end
 
     def self.remove_unecessary_units(hash)
@@ -477,6 +479,14 @@ def self.generate_schedule_indices_from_date(hash)
       hash
     end
 
+    def self.generate_linked_service_ids_for_relations(hash)
+      hash[:relations]&.each{ |relation|
+        next unless relation[:linked_ids]&.any?
+
+        relation[:linked_service_ids] = relation[:linked_ids].select{ |id| hash[:services]&.any?{ |s| s[:id] == id } }
+      }
+    end
+
     def configuration=(configuration)
       self.config = configuration
       self.preprocessing = configuration[:preprocessing] if configuration[:preprocessing]