Web Forms :: Merge Two Stored Procedures In SQL Server

I use below store procedure that don't allow insert duplicate data in database in code column 

ALTER procedure [dbo].[insertestate1]
@position nvarchar(max)
,@Transfer nvarchar(20)
,@Type nvarchar(20)
,@Behcode nvarchar(10)

[Code] ....

And this is my other SP that  I define Condition ,and  according to that condition  it update or insert data in database

USE [behtop]
GO
/****** Object: StoredProcedure [dbo].[insertestate] Script Date: 10/04/2012 11:36:21 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER procedure [dbo].[insertestate]

[Code] ....

In first SP @code parameter is column in table that I don't want accept duplicate value and condition of that is:

IF NOT EXISTS(SELECT behcode FROM Estate_p WHERE code = @code)

And  in second SP I have @code parameter that I don't want it insert duplicate data on it too. But here condition is 

IF @id > 0 AND EXISTS(SELECT behcode FROM Estate_p WHERE id=@id)

Now I want merge two SP .. How I can do it?