Using firewall-cmd to restrict ICMP echo request and ICMP echo reply to local subnet?

[Tom Leach]

Hello, I'm transitioning over to firewalld from iptables and one of the 
iptables rules that I had was to allow ICMP pings to/from other systems 
on my local subnet, but block ICMP pings to/from systems outside of my 
local subnet.
The systems are all clients so I don't have a LAN/WAN dual network port 
setup.

When firewall-cmd translates the old iptables into firewalld rules, the 
subnet portion is removed and I'm left with a block all/unblock all 
situation.
Is there a way to use either a rich rule or a direct rule to allow full 
ICMP access to specified subnets and block all others?
I'm looking for something like:
     firewall-cmd --permanent --zone=public --add-rich-rule='rule 
protocol=icmp source address="192.168.100.0/24" accept'
     firewall-cmd --permanent --zone=public 
--add-icmp-block=echo-reply,echo-request
which I expect to allow any ICMP packet originating from a host in 
192.168.100.0/24 but all others are dropped.
Thanks!
Tom Leach