Open Starting new MMS group message on Chrome

Hello,
I am having an issue starting a new MMS group message from the Chrome extension
I go to the SMS/Phone tab, then hover over the + to start a new message, then click the pen to do a text message instead of a call. This presents me with my contact list. When I select a contact, it immediately pushes me into a one on one SMS with that person, and I cannot figure out how to add any more people to that message.
However, in my list of existing conversations, I have no issue clicking into an existing group message and sending and receiving messages there.

So, this appears to only be an issue when creating a new MMS group message.

Help would be very much appreciated, thanks!!