I have a bit of a problem with my dataset. I am trying to delete the consecutive rows but only in an alternate way!

my data

group   ID  result
ABCD    19  Keep
ABCDE   2   Keep
ABCDE   3   delete
ABCDE   4   Keep
ABCDE   5   delete
ABCDE   6   Keep
ABCDE   22  Keep
ABCDEF  18  Keep
ABCDEFG 21  Keep
ABCDEFG 22  delete
ABCDEFG 23  Keep

I have tried couple things but fail to keep the alternate rows, it is deleting all consecutive ones. Thanks in advance