The easiest way to generate an extra number is to use Add> Logic Element> Count and set the initial value of the counter, followed by the maximum value, and also set the link name.
You can access the link name by specifying $ {reference name} in the request.
"" > " " > " "
, , ${__ V ($ {__ Random (30002,40000,)})}
, 
Bean Shell scripting Add > Pre processor > BeanShell Processor.
, .