How do you use a parameter in a SQL IN statement?

I have the following in a large SQL command in cmd.CommandText.

 WHERE Claims.GroupNbr IN('@grpno1','@grpno2') 

After the cmd.CommandText I have:

         cmd.Parameters.AddWithValue("@grpno1", groupno1); 
         cmd.Parameters.AddWithValue("@grpno2", groupno2);




 

I try to print the cmd.CommandText after this but it does not show the substitution. 
How can I see the substitution?





 

But the main question is can I do this or how can I do this another way?  

I know the command works if it is:






 
 WHERE Claims.GroupNbr = @grpno1

 
Thanks for any help,
arep