I am groovy beginner

I have two lists 

```
    ​list1 = [[1,'Rob','Ben', 'Ni', 'cool'],[2,'Jack','Jo','Raj','Giri']....[]...] 

   list2 = [[null,'2013-10-09','2013-10-10'],[4, '2013-10-11', '2013-10-12']]

```

i want to combine these lists in following format

```
 list3  = [[1, null, '2013-10-09', '2013-10-10', 'Rob', 'Ben', 'Ni', 'cool'], [2, 4, '2013-10-11', '2013-10-12', 'Jack', 'Jo', 'Raj', 'Giri']]

```

tried [Groovy: Add some element of list to another list](https://stackoverflow.com/questions/19182637/groovy-add-some-element-of-list-to-another-list/19191738?noredirect=1#19191738)

but couldn't do in this format.. help me!