[PD] create list by header message

[Peter P.]

Hi,

this might be totally simple, but I am wondering what is the most
elegant way of creating a list out of individual messages

12
23
34
45

meaning a list which holds four items, and which is always created at
the number '12', and sent out at the nu,ner '45', yielding:

list 12 23 34 45

so some kind of parallelization depending on a header value (12).

thanks for any pointers
best, P