for (int j = 0; j < subtipColumns.Count - 1; j++)
{
    float totalHeight = 0f;
    int step = 0;
    while (step < subtipColumns[j].childCount)
    {
        RectTransform rect = (RectTransform)subtipColumns[j].GetChild(step);
        totalHeight += rect.rect.height + margin;
        if (totalHeight > topBorder)
        {
            rect.SetParent(subtipColumns[j + 1], false);
        }
        else
        {
            step++;
        }
    }
}