communication media 110 include well known local area networks lan such as ethernet wide area networks wan telephone modem links wireless or cellular or other well known and conventional computer networking technology the configuration and interconnection of computer system components as illustrated in fig1 is well known to those of ordinary skill in the art referring now to fig2 a block diagram illustrating the software architecture 205 of the exemplary computer system of fig1 is shown the exemplary computer system comprises software operably disposed within random access memory ram 102 and executed by processor 101 the software architecture 205 comprises a meeting manager component 210 a display manager component 212 a mid level cm component 215 a low level cm component 216 and an optional mass storage manger component 214 the two cms 215 and 216 jointly provide a software interface to the communication hardware interface 108 the two cms 215 and 216 comprise processing logic and data specific to the communication medium 110 being used for a particular conferencing application in general the two cms 215 and 216 provide an indication to meeting manager 210 when a new conference participant connects to communications medium 110 or when a message transferred across communications medium 110 arrives for processing by meeting manager 210 the two cms 215 and 216 are also responsible for sending messages across communications medium 110 on behalf of the meeting manager 210 in particular the two cms 215 and 216 incorporate the teachings of the present invention allowing the meeting manager 210 to selectively designate subsets of the conference participants as recipients of the messages instead of the traditional one or all binary destinations the meeting manager 210 communicates with the mid level cm 215 through interface 235 which in turn communicates with the low level.