Layout table from PHP array

I'm dealing with a table that is formed from an array and I do not give with the solution, I would greatly appreciate if you could horientar me. The problem is that I can not put in the same row and on the corresponding day the schools that have the same time. Thank you very much

this is the table I want to get:

and this is the code I have:

$Caja = "select Grupos.Nombre,Grupos.Dia_activ1,Grupos.Hora_ini1,Grupos.Hora_fin1,group_concat(Profesores.Color) from Grupos inner join Profesores on (Grupos.profe1 = Profesores.id) where Grupos.Zona='".$cp."' group by Grupos.Nombre order by Grupos.Hora_ini1,Grupos.Dia_activ1 ASC";

$table = mysqli_query($con, $Caja); 
$arr = array();
while($row22 = mysqli_fetch_row($table))
{
    $row22['Grupos.Nombre'] = explode(",", $row22['Grupos.Nombre']);
    $arr[] = $row22;
    $numRows22++;
} 
$ultimo=0;  
$p=0;       
foreach($arr as $row){ 
$horas=$row[2].' a '.$row[3];
if($horas<>$ultimo){
$ultimo=$horas;
$colorprofe=$row[4];

        echo "<tr>";
            echo "<td>" . $horas ."</td>";
            for($w=1; $w<6; $w++){
            if($row[1]==$w){
            echo " <td>
            <button style='background: #".$row[4]."' class='btn btn-default' data-toggle='modal'>" . $row[5] . "</button></td>";


            }else{echo "<td></td>";}
            }

  }else{

             echo "<td></td>";
            for($w=1; $w<6; $w++){
            if($row[1]==$w){
            echo " <td>
            <button style='background: #".$row[4]."' class='btn btn-default' data-toggle='modal'>" . $row[5] . "</button></td>";
            }else{echo "<td></td>";}
            }

  }  

}