Overwrite a specific field on a specific node
As I understand, you want a to display the same block which lists some node information in different pages and want to avoide listing some specific nodes in some specific pages. You can make use of views filter with 'Global: PHP' and have code similar to as below :


if (arg(0) == 'node') {// Set your condition here.
  if ($data->nid == NID_YOU_WANT_TO_RESTRICT) {// Set the NID you want to restrict
    return TRUE;
  }
}


Note : To consider multiple job postings in future, you just need to set the path condition accordingly.

Hope it helps