print all max values in text file using awk

I'm trying to print out all the max values in one column So the input looks like this

John.      Marketing.   5000.  
Marcus.    Manager.     9500.  
Jason.     SW           9500.  
Cindy.     Developer.   6000.

the output I want is

name: Marcus, sal: 9500.    
   name: Jason, sal: 9500

so far, my code is

BEGIN {a=0}

    {
        if ($3> a)
           max=$3;
        output=$1
     }

    END{
      print "name: ", output, "sal:", max
    }