Dial a list of destination phone numbers and add them to a conference.
Use conference_set_auto_outcall to have mod_conference call one or more conferees when a conference starts. To have it call more than one endpoint, simply repeat the conference_set_auto_outcall action in the dialplan for each destination number.
Here is an example of using conference_set_auto_outcall with some of the other conference_auto_outcall_* parameters to start a conference when someone dials 12345. Extensions 1000, 1001, and 1004 will be dialed when the conference starts.
Because 1004 is in a noisy environment that station has the "mute" flag set initially; when that station presses 0 it will toggle the mute as normal, it simply starts in the muted state to avoid disrupting the conference with noise. Note the use of square brackets around the mute flags for 1004; when FS builds the originate string the square brackets apply their contents only to that one destination, not to the whole dial string.
It is also possible to autocall multiple destination at once, just remember to escape your variables if you have more than one or any non-escaped chars in it. Again, note the use of square brackets to apply settings to only one destination.
Overall, it is much easier to use the individual outcall lines as shown above.
"Mad Boss" example extensions in default XML dialplan