[Zope] Persistent method

Hi Is it possible to have a persistent method/class/process running in the ZOPE framework? For example an online trading site would have some connectors (CORBA or XLMRPC) to an external system to do the trades. The connectors can be a python class. This class will place an order and have to wait for a reply, but since a reply can take too much time, one would have an asynchronous call. The class/process still needs to stay resident so that it can act on the reply, e.g. write reply to database/send mail to users etc. Also it could monitor clients portfolios and send e-mail or some other notification when a specific share is above or below a certain threshold. Any suggestions? Regards Roelof Naude