I do not agree that the more intelligent animals are necessarily the best candidates for running two dogs together and I sure wouldnt try a pack of adult dogs.I think it is more about the individuals nature rather than a show of intelligence.Although I do believe the smarter animal with the right nature will most always be more tolerant when socializing these dogs.I have a female who is very smart and has the right nature most of the time but for unexplannable reason she has shown me multiple times to stay close and do not take my attention off her for even a minute.This may work with some lines but definitely not mine.I have broke up multiple dog accidents more than once with young adults.Lesson learned.I do agree its an interesting thread and it is nice to read others experiences.