how to hide QgraphicsItem !!!

[peace_comp]

Hi..
I have a problem of how to use correcty the QGraphicsItemGroup ..
well. my application is about zooming on a map .. so depending on the zoom I should display or hide some details..
for example to put the names of cities after zooming I used:

void myview::zoomingin(){
 
for (int i=0;i<5;i++){
QGraphicsTextItem * txt=new  QGraphicsTextItem(citiesName[i]);
txt->setPos(citiesX[i],citiesY[i]);
scene->addItem(txt);
group->addToGroup(txt);
  }
graphicsView->scale(1.2,1.2);
}

void myview::zoomingin(){

for (int i=0;i<5;i++){
QGraphicsTextItem * txt=new  QGraphicsTextItem(citiesName[i]);
txt->setPos(citiesX[i],citiesY[i]);
scene->addItem(txt);
group->addToGroup(txt);
  }
graphicsView->scale(1.2,1.2);
}

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>> citiesName,citiesX,citiesY are QList containin' the names and coordonates of each citie..

then I should hide them when we zoom out .. I try to used:

void myview::zoomingout(){
 
     scene->destroyItemGroup(group);
 
     graphicsView->scale(1/1.2,1/1.2);
     }

void myview::zoomingout(){
   
     scene->destroyItemGroup(group);
  
     graphicsView->scale(1/1.2,1/1.2);
     }

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but it doesnt work .. nd when the group became empty it stucks!!

plz if someOne have a idea !!!!!!!!!!!!!!!!!!!!!!