Network isolation?

[MR ZenWiz]

I have a few computers around the house, but for some reason I don't
see, from one of them I can't connect to any of the others.

Basic setup:
- Desktop, wire connection to the router, connects fine with all the
other wifi machines.
- Personal laptop - wifi connection that is proven almost fully
functional - see below.
- Two other laptops - also on wifi, exhibiting no problems.

However:

My laptop cannot ping any of the others on the wifi.  It has no
trouble pinging google.com, browsing the web and running zoom
meetings.

>From my desktop, I can ssh into the laptop and successfully execute
most commands.  However, even though I am ssh logged-into that laptop
from the desktop, the laptop cannot even ping the desktop.

Any pointers or guidance would be greatly appreciated.

Thanks.

Mark