Stream manycam output to HDMI port

I have the output of my PC (laptop) HDMI sent to a projector, and also to a digital recorder.

How can I route the output of ManyCam on the PC to go to that port?

It seems like one approach is to find some display program, map it to a second monitor full-scree, and hen use that as the HDMI output port.

This seems a bit convoluted, and not sure of any good program for such a display.
And I wonder if I could send it to a virtual monitor instead, and map that to the HDMI out port?

I also sent this to their support - no reply - somewhat disappointing.