How to Have Two Different Color Palettes on the Same Canvas ?

{
   gStyle->SetOptStat(0);
   TCanvas *c = new TCanvas("c","c",600,600);
   c->Divide(1,2);
 
   TH2F *h1 = new TH2F("h1","h1",40,-4,4,40,-4,4);
   TH2F *h2 = new TH2F("h2","h2",40,-4,4,40,-4,4);
   Double_t a,b;
   for (Int_t i=0;i<5000;i++) {
      gRandom->Rannor(a,b);
      h1->Fill(a-1.5,b-1.5);
      h2->Fill(a+1.5,b+1.5);
   }
   TExec *ex1 = new TExec("ex1","gStyle->SetPalette(0);");
   TExec *ex2 = new TExec("ex2","gStyle->SetPalette(1);");
 
   c->cd(1);
   h1->Draw("col");
   ex1->Draw();
   h1->Draw("colz same");
 
   c->cd(2);
   h2->Draw("col");
   ex2->Draw();
   h2->Draw("colz same");
}