Remove Duplicate values

Hi All,

  The following is the input structure

<ContextChange>

10

abc

asd

qwe

<ContextChange>

20

qwe

ert

hjk

<ContextChange>

10

lkj

cvb

rfg

<ContextChange>

now basing on the first field , output should be segregated like following

<ContextChange>

10

abc

asd

qwe

lkj

cvb

rfg

<ContextChange>

20

qwe

ert

hjk

<ContextChange>

the all values under the same qualifier should come under one context.Kindly help.

Regards,