Create feeder in the first exec to use it in the second.

Hello, dear community!
Please help with creating dynamic feeder. I need to transfer data from multiple responses in first exec to use them in the second exec but it looks like all feeders and data for requests are collected during compilation. I send a pack of files to my storage and collect their IDs. I need to use all these IDs in further execs but itemStorages.keySet.toList arrives empty to second exec. The same happens when I try to create .csv in uploadAndCollect - it crashes during compilation `cause .csv is absent by then.

val uploadAndCollect = exec(sendItemBeforeRedirect(image)).exec(sendItemRedirected(image)
  .exec(session => {
    val itemId = Integer.valueOf(session.attributes("item_id").toString)
    val itemStorage = session.attributes("redirectURL").toString.split("/")(2)
    itemStorages += (itemId -> itemStorage)
    if (itemsCountBefore.contains(itemStorage)) itemsCountBefore(itemStorage) = itemsCountBefore(itemStorage) + 1
    else itemsCountBefore += (itemStorage -> 1)