diff --git a/lib/brainstem/dsl/association.rb b/lib/brainstem/dsl/association.rb
index ce216659..7e56b5e3 100644
--- a/lib/brainstem/dsl/association.rb
+++ b/lib/brainstem/dsl/association.rb
@@ -37,12 +37,14 @@ def method_name
         end
       end
 
-      def run_on(model, context, helper_instance = Object.new)
+      def run_on(model, context, helper_instance = Object.new, lookup_options = {})
         if options[:lookup]
           run_on_with_lookup(model, context, helper_instance)
         elsif options[:dynamic]
           proc = options[:dynamic]
-          if proc.arity == 1
+          if proc.arity == -2
+            helper_instance.instance_exec(model, lookup_options, &proc)
+          elsif proc.arity == 1
             helper_instance.instance_exec(model, &proc)
           else
             helper_instance.instance_exec(&proc)
diff --git a/lib/brainstem/presenter.rb b/lib/brainstem/presenter.rb
index 851d7163..fe9dcaf3 100644
--- a/lib/brainstem/presenter.rb
+++ b/lib/brainstem/presenter.rb
@@ -334,7 +334,9 @@ def load_associations!(model, struct, context, options)
         # If this association has been explictly requested, execute the association here.  Additionally, store
         # the loaded models in the :load_associations_into hash for later use.
         if context[:association_objects_by_name][external_name]
-          associated_model_or_models = association.run_on(model, context, context[:helper_instance])
+          lookup_options = {}
+          lookup_options[:firstFiftyAssociations] = true if options[:firstFiftyAssociations]
+          associated_model_or_models = association.run_on(model, context, context[:helper_instance], lookup_options)
 
           if options[:load_associations_into]
             Array(associated_model_or_models).flatten.each do |associated_model|
diff --git a/lib/brainstem/presenter_collection.rb b/lib/brainstem/presenter_collection.rb
index 897b87dc..3b96f55f 100644
--- a/lib/brainstem/presenter_collection.rb
+++ b/lib/brainstem/presenter_collection.rb
@@ -93,10 +93,13 @@ def structure_response(presented_class, primary_models, strategy, count, options
 
       if primary_models.length > 0
         associated_models = {}
+        group_present_options = {optional_fields: optional_fields, load_associations_into: associated_models}
+        if options[:params]["firstFiftyAssociations"]
+          group_present_options.merge!({firstFiftyAssociations: true})
+        end
         presented_primary_models = options[:primary_presenter].group_present(primary_models,
                                                                              selected_associations.map(&:name),
-                                                                             optional_fields: optional_fields,
-                                                                             load_associations_into: associated_models)
+                                                                             group_present_options)
 
         struct[brainstem_key] = presented_primary_models.each.with_object({}) { |model, obj| obj[model['id']] = model }
         struct['results'] = presented_primary_models.map { |model| { 'key' => brainstem_key, 'id' => model['id'] } }