[ns] How set difference transmission rage

[Phitsanu Eamsomboon]

Dear all
     Please tell me if you know how can I set tcl code for set 50 node
communicated in 250 m range and another 50 nodes in 500 m range ?
      I 'd like to see some code for set it by having difference range
communicated

Anyone help me, Please

Best regard
Phitsanu