One way calling card conferencing

A feature I would love to see is a one-way calling card conference. Do just like now, and copy calling cards into a folder. Select the folder and choose to IM all on-line people in it. But have a checkbox in that dialog to make it one-way. Make that a persistent setting, so it remains in effect for that folder each time you IM that group of people, unless you change the check box.

Alternatively, maybe there could be a setting where one could reply, but only the person originating the call will hear those replies?

This would be primarily for event announcements to club regulars. The host can announce, but no one can reply, except by doing a private IM back to them. It is to cut back on the IM spam caused by a flood of "TP me to the event please!" replies from other people who get the same event announcements.