diff --git a/lib/exactor/common.ex b/lib/exactor/common.ex
new file mode 100644
index 0000000..fb0204d
--- /dev/null
+++ b/lib/exactor/common.ex
@@ -0,0 +1,22 @@
+defmodule ExActor.Common do
+  @moduledoc false
+
+  # This module adds common functionality to all ExActor behaviours.
+  defmacro __using__(_opts) do
+    quote do
+      @doc """
+      By default, the `server` argument given
+      to the different interface functions, is expected to be a process identifier,
+      unless overridden by the `export:` option.
+
+      But by providing a custom implementation of `server_pid/1`, you can map an identifier
+      to a PID by some other means.
+      """
+      def server_pid(server_reference) do
+        server_reference
+      end
+
+      defoverridable [server_pid: 1]
+    end
+  end
+end
diff --git a/lib/exactor/empty.ex b/lib/exactor/empty.ex
index abe0c69..bc6b312 100644
--- a/lib/exactor/empty.ex
+++ b/lib/exactor/empty.ex
@@ -21,6 +21,7 @@ defmodule ExActor.Empty do
   defmacro __using__(opts) do
     quote do
       @behaviour :gen_server
+      use ExActor.Common
 
       @generated_funs MapSet.new
 
diff --git a/lib/exactor/gen_server.ex b/lib/exactor/gen_server.ex
index 7607c58..2a358cb 100644
--- a/lib/exactor/gen_server.ex
+++ b/lib/exactor/gen_server.ex
@@ -19,6 +19,7 @@ defmodule ExActor.GenServer do
   defmacro __using__(opts) do
     quote do
       use GenServer
+      use ExActor.Common
 
       @generated_funs MapSet.new
 
diff --git a/lib/exactor/operations.ex b/lib/exactor/operations.ex
index efd9f3f..2375191 100644
--- a/lib/exactor/operations.ex
+++ b/lib/exactor/operations.ex
@@ -570,7 +570,8 @@ defmodule ExActor.Operations do
       server_fun: server_fun(type),
       interface_args: Macro.escape(interface_args(interface_matches, options), unquote: true),
       gen_server_args: Macro.escape(gen_server_args(options, type, payload), unquote: true),
-      guard: Macro.escape(guard(options, :interface), unquote: true)
+      guard: Macro.escape(guard(options, :interface), unquote: true),
+      export_option: Macro.escape(options[:export], unquote: true)
     ] do
       {interface_args, gen_server_args} =
         unless type in [:multicall, :abcast] do
@@ -582,31 +583,32 @@ defmodule ExActor.Operations do
           }
         end
 
-      arity = length(interface_args)
-      unless private do
-        if guard do
-          def unquote(req_name)(unquote_splicing(interface_args))
-            when unquote(guard)
-          do
-            GenServer.unquote(server_fun)(unquote_splicing(gen_server_args))
-          end
+      interface_gen_server_args =
+        if type in [:multicall, :abcast] || export_option do
+          gen_server_args
         else
-          def unquote(req_name)(unquote_splicing(interface_args)) do
-            GenServer.unquote(server_fun)(unquote_splicing(gen_server_args))
-          end
-        end
-      else
-        if guard do
-          defp unquote(req_name)(unquote_splicing(interface_args))
-            when unquote(guard)
-          do
-            GenServer.unquote(server_fun)(unquote_splicing(gen_server_args))
-          end
-        else
-          defp unquote(req_name)(unquote_splicing(interface_args)) do
-            GenServer.unquote(server_fun)(unquote_splicing(gen_server_args))
-          end
+            # Extract the server reference as first argument,
+            # And call `server_pid/1` on it inside the interface implementation.
+            # (But not in the function head)
+            [server_ref | gen_server_args_tail] = gen_server_args
+            server_pid_quote = quote(do: server_pid(unquote(server_ref)))
+            [server_pid_quote | gen_server_args_tail]
         end
+
+      interface_body =
+        quote do
+        GenServer.unquote(server_fun)(unquote_splicing(interface_gen_server_args))
+      end
+
+      cond do
+        private == nil && guard == nil ->
+          def unquote(req_name)(unquote_splicing(interface_args)), do: unquote(interface_body)
+        private == nil && guard != nil ->
+          def unquote(req_name)(unquote_splicing(interface_args)) when unquote(guard), do: unquote(interface_body)
+        private != nil && guard == nil ->
+          defp unquote(req_name)(unquote_splicing(interface_args)), do: unquote(interface_body)
+        private != nil && guard != nil ->
+          defp unquote(req_name)(unquote_splicing(interface_args)) when unquote(guard), do: unquote(interface_body)
       end
     end
   end
diff --git a/lib/exactor/strict.ex b/lib/exactor/strict.ex
index 5b201bc..d551c20 100644
--- a/lib/exactor/strict.ex
+++ b/lib/exactor/strict.ex
@@ -28,6 +28,7 @@ defmodule ExActor.Strict do
   defmacro __using__(opts) do
     quote do
       use ExActor.Behaviour.Strict
+      use ExActor.Common
 
       @generated_funs MapSet.new
 
diff --git a/lib/exactor/tolerant.ex b/lib/exactor/tolerant.ex
index d7fb6b5..37eea9b 100644
--- a/lib/exactor/tolerant.ex
+++ b/lib/exactor/tolerant.ex
@@ -23,6 +23,7 @@ defmodule ExActor.Tolerant do
   defmacro __using__(opts) do
     quote do
       use ExActor.Behaviour.Tolerant
+      use ExActor.Common
 
       @generated_funs MapSet.new