domain vs realestate.com.au

How do these 2 sites create the top 10 or top 20 properties for a suburb search

Example - Bentleigh 3204

domain:

• LJ Hooker 8 of the top 10
  
• Ray White 1 and
  
• Buxton 1
  

realestate.com.au:

• hocking stuart 1,
  
• LJHooker 4,
  
• Buxton 3,
  
• Wilson Pride 1,
  
• Sandy Anderson 1
  
• hocking stuart +1 for advertised top space
  

Even when you go top 20
domain give precedence to LJH for another 3 spots 11, 12 & 13
realestate.com.au give over 6 spots to hockingstuart.
Yet Buxtons probably are leading the listings in the Bentleigh area.
How does it work?