awk columnwise adjacent match checking program

Hi,

For the below problem, awk script is needed..

input file :

jill
jack
jill
jill
jack
jill
jack
jill

Required:
here,
i need to check from first line.
reference is jack. jill need to verified with next line jack. if found print

jill & jack combination hill1 
jack & jill & jill & jack combination hill2
jack&jill&jack combination hill3
jack &jill combination hill1

Thanks in advance
vasanth