How can I change one object only when one other object is selected?

Good night people!! I'm currently browsing MEL and expressions ... And I'm trying to do something like this: if I select one object I deactivate one property from another ... But I'm having problems with the object selection denomination ... The following is an example ... .

If (select pCube1-r on)   {   PCube2.visibility = 0;   }

I have tried with strings too but it didn't work...

global proc myscript()
  {
    string $a[] = ls -sl;

      if ($a[0] == "pCube1")

        hide = "pCube2";

     else;
 }

scriptJob -e"SelectionChanged"
"myScript";

Can someone help? Obs: My English is not so good, sorry!

Thank you very much!!!