Aaron is spot on.
I can give you a quick example to assist.
If I had a parent list with 5 items ...
1 Item 1
2 Item 2
3 Item 3
4 Item 4
5 Item 5
... and we wanted to add 1 more item to this parent list which was determined on how another question was asked, we could add in a new item 6 to the parent list which could be something like this ...
6 [%ListLabel(Q1ConList,1)%]
... where Q1ConList is a constructed list that gets all the brands you have used in the last 12 months at Q1. Assume that constructed list is randomised, then item 6 grabs the 1st code from that constructed brand list and slots it into the new parent list you have.
So the new parent list would now look like this ...
1 Item 1
2 Item 2
3 Item 3
4 Item 4
5 Item 5
6 [%ListLabel(Q1ConList,1)%]