SightSpeed PLUS users can invite up to 3 other contacts for a multiparty call. Here’s how:

1) After logging in, click the Voice & Video Calls tab, then the Multi-Party mini tab.
2) Select the contacts you wish to invite from your contact list by clicking on a contact, and then clicking the Add button to place them into the Particpants box.
3) To remove a contact you’ve added, click the X next to the text field.
4) When you have finished, click the "Start the Multi-Party Conference" button. Offline contacts will receive an email notification of the invitation, and ask them to join by logging into SightSpeed.