Select or remove successive indices from sublists

Hi,

How do I select successive indices from a list with sublists?

For example:

Let’s say I have a list with sublists a,b and c.
Each sublists contains 3 items.
a1,a2,a3
b1,b2,b3
c1,c2,c3

I want to select and remove a1,b2,c3.

I’m sure it should be pretty simple, but I couldn’t find a way.

Solved it. Had to set the RemoveItemAtIndex lacing to longest.