I have a table like the one below. How can I get Excel to put borders around groups with the same number in the 4th column so that there is a border around the groups. I was thinking conditional formatting could do it but I can't think how. So I think the only option is a macro. Could anybody help?

    1   64436   549419  1       
    2   64437   549420  1       
    3   64438   549421  1       
    4   64439   549422  1       
    5   64440   549423  1       
    6   64441   549424  1       
    7   64442   549425  1       
    8   64443   549426  1       
    9   64444   549427  1       
    10  64445   549428  1       
    11  64446   549429  1       
    12  64447   549430  1       
    13  64448   549431  2       
    14  64449   549432  2       
    15  64450   549433  2       
    16  64451   549434  2       
    17  64452   549435  2       
    18  64453   549436  2       
    19  64454   549437  2       
    20  64455   549438  2       
    21  64456   549439  2       
    22  64457   549440  4       
    23  64458   549441  4       
    24  64459   549442  5       
    25  64460   549443  5       
    26  64461   549444  5       
    27  64462   549445  5       
    28  64463   549446  5       
    29  64464   549447  5       
    30  64465   549448  6       
    31  64466   549449  6       
    32  64467   549450  6       
    33  64468   549451  6       
    34  64469   549452  6       
    35  64470   549453  6       
    36  64471   549454  6       
    37  64472   549455  9       
    38  64473   549456  9       
    39  64474   549457  9