Help with syntax for an if/while statement involving simultaneous note events.

First, sorry about the code below. The paragraph/code bIock isn't showing up for me on the highlighted text.

For my question... I want to have a group allowed/disallowed when a pair of keyswitches are pressed and have a button reflect that change. I have things working fine with 1 keyswitch as follows...

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if ($btn_001 = 0)
  while ($EVENT_NOTE = $keyswitch1)
    $btn_001 := 1
    $grp_001_active := 1  
  end while
end if

if ($btn_001 = 1)
  while ($EVENT_NOTE = $keyswitch1)
    $btn_001 := 0
    $grp_001_active := 0  
  end while
end if

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But the following doesn't seem to work. I also tried nesting a while within a while to no avail...

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if ($btn_001 = 0)
  while ($EVENT_NOTE = $keyswitch1 and $EVENT_NOTE = $keyswitch2)
    $btn_001 := 1
    $grp_001_active := 1  
  end while
end if

if ($btn_001 = 1)
  while ($EVENT_NOTE = $keyswitch1 and $EVENT_NOTE = $keyswitch2)
    $btn_001 := 0
    $grp_001_active := 0  
  end while
end if

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Any thoughts on the proper syntax in this case?