They are based on a layerset.
You could select both by...
#target photoshop;
if(activeDocument.activeLayer.name.match(/Frame$/)){
var Frame1 = activeDocument.activeLayer.id;
var Frame2 = activeDocument.activeLayer.layers[0].id;
selectLayerById(Frame1);
selectLayerById(Frame2,true);
}
function selectLayerById(id,add){
var ref = new ActionReference();
ref.putIdentifier(charIDToTypeID('Lyr '), id);
var desc = new ActionDescriptor();
desc.putReference(charIDToTypeID("null"), ref );
if(add) desc.putEnumerated( stringIDToTypeID( "selectionModifier" ), stringIDToTypeID( "selectionModifierType" ), stringIDToTypeID( "addToSelection" ) );
desc.putBoolean( charIDToTypeID( "MkVs" ), false );
try{
executeAction(charIDToTypeID("slct"), desc, DialogModes.NO );
}catch(e){}
};
Another version, that checks which is selected (must have a frame layer selected)
#target photoshop;
if(app.activeDocument.activeLayer.blendMode == BlendMode.PASSTHROUGH){
var Frame1 = activeDocument.activeLayer.id;
var Frame2 = activeDocument.activeLayer.layers[0].id;
}else{
var Frame1 = activeDocument.activeLayer.parent.id;
var Frame2 = activeDocument.activeLayer.id;
}
selectLayerById(Frame1);
selectLayerById(Frame2,true);
function selectLayerById(id,add){
var ref = new ActionReference();
ref.putIdentifier(charIDToTypeID('Lyr '), id);
var desc = new ActionDescriptor();
desc.putReference(charIDToTypeID("null"), ref );
if(add) desc.putEnumerated( stringIDToTypeID( "selectionModifier" ), stringIDToTypeID( "selectionModifierType" ), stringIDToTypeID( "addToSelection" ) );
desc.putBoolean( charIDToTypeID( "MkVs" ), false );
try{
executeAction(charIDToTypeID("slct"), desc, DialogModes.NO );
}catch(e){}
};