Are you using Wireshark to monitor and are worried that you will have to open two Wiresharks to monitor a single SCTP association?
If that is the case, then you can just monitor in promiscuous mode and apply sctp as filter or port 2905 (or the port on which the SCTP association is running).
Promiscuous mode, however, requires root (or admin) privileges.
If you do not have Promiscuous mode, then as Jason suggested you will have to monitor all IP's which are part of the association. You can, of course, merge all the separate pcap files into one and then analyze the association traffic.
Ofcourse, if this is no way related to Wireshark, then all of this is gibberish :)