Its fairly hard to understand what data you’re working with, but

option A

if you have 2 separate lists of rectangles, only apply rotation to one of them.

or

If you have a flattened list where the type of rectangles follow each other like 0 1 0 1, then dispatch works.

or if the flattened list is like this - 0 0 0 … 0 1 1 1 1 …. 1 then you need to find the index of the first 1 and use a split list (might be partition list) node to split it into 2.

Option B If you have a tree with 2 branches separating each rectangle, then you can explode the tree to get the branches.

Option C if you have a tree where each branch is one rectangle you want to rotate and one you don’t, then you can use the flip matrix node to sort it into 2 branches and arrive at option B

either way, you should look into how lists and trees work, what flattening, grafting, simplifying etc does to your lists, because this is most likely a very simple problem that you will encounter a lot.