compare two successive rows - group by

i have a model as below

ID     Date                    BoitierNumber
 1      07/04/2012 14:01:46     1
 2      07/04/2012 14:01:50     2
 3      07/04/2012 14:01:50     3
 4      07/04/2012 14:01:56     1
 5      07/04/2012 14:02:06     1
 6      07/04/2012 14:02:10     2
 

I have grouped rows by (BoitierNumber)

*boitier Number 1
 
  1      07/04/2012 14:01:46
  4      07/04/2012 14:01:56 
  5      07/04/2012 14:02:06
 
 *boitier Number 2
 
  2      07/04/2012 14:01:50
  6      07/04/2012 14:02:10 
 
 *boitier Number 3
 
  3      07/04/2012 14:01:50
 

To do this i have used this code

var groups = context.Essais.GroupBy(p => p.BoitierNumber)
                 .Select(g => new { GroupName = g.Key, Members = g });
 
         foreach (var g in groups)
         {
             Console.WriteLine("Members of {0}", g.GroupName);
 
             foreach (var member in g.Members.OrderBy(x=>x.Id))
             {
                 Console.WriteLine("{0}     {1}", member.Id,member.Date);
             }
 
         }
 

For the moment everything works fine
now i want to compare the date of two successives grouped rows
if row[i].date>row[i-1].date i will delete row[i-1]

*boitier Number 1
 
  1      07/04/2012 14:01:46
  4      07/04/2012 14:01:56 
 
  boitier Number 1 ---> Date of row of Id 4 > Date of row of ID 1
  then i will delete row of ID 1
 

Please Help, i don't know how to do this ?

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