This might be a novice question, but where in a stream do leads join? For example, say I have seven emails in a stream. Lead A transitions to said stream after it has been running for a month. Would Lead A start receiving emails from the top of the stream (i.e., sequentially from 1-7), or would it start receiving emails from wherever the other leads are at at that point in time (i.e., it would begin on email 3)? If it is the second (they join in the middle of a series of emails), is there a way to make it so they start at the top?