This is possibly a ludicrous idea, but hopefully not quite as ludicrous as the title suggests.
We know the Romans built forts in Scotland in an attempt to stop the people we know as Picts coming down and raiding the the would be settlements in the south. Tacitus's Agricola suggests that the Picts were not charmed by this but other than that we know very little about the impacts on their society etc.
However, what we do know is that in the nineteenth century the United States started colonising the Prairies, the native inhabitants were less than pleased. Like the Romans, the United States built forts to protect settlements, and that this had an impact on the social organisation and possibly the material culture of the native American tribes.
Unlike the Picts we have credible accounts of what the native Americans thought about the changes, so we could use them as an imperfect analogy, and thus if we see that native Americans started to form larger groupings we could then go and see from the archaeological record if the picts appeared to react in the same way.
Certainly, it looks as if, like the Lakota, the Picts reacted by forming larger federations and groupings ...