Code:
$ cat inputfile
Time,A,Server1,KPI1,data1
Time,A,Server1,KPI2,data2
Time,A,Server1,KPI3,data3
Time,A,Server1,KPI4,data4
Time,A,Server1,KPI5,data5
Time,A,Server2,KPI1,data6
Time,A,Server2,KPI2,data7
Time,A,Server2,KPI3,data8
Time,A,Server2,KPI4,data9
Time,A,Server2,KPI5,data10
Time,A,Server3,KPI1,data11
Time,A,Server3,KPI2,data12
Time,A,Server3,KPI3,data13
Time,A,Server3,KPI4,data14
Time,A,Server3,KPI5,data15
Time,A,Server4,KPI1,data16
Time,A,Server4,KPI2,data17
Time,A,Server4,KPI3,data18
Time,A,Server4,KPI4,data19
Time,A,Server4,KPI5,data20