[rocky] How to configure equal cost multi-path routing with NetworkManager?

Hi folks,

With CentOS 7/Rocky 8 and "network-scripts" I was able to configure static routes using "equal cost multi-path" (ECMP) routing. /etc/sysconfig/network-scripts/route-eth0 would contain a line like

172.16.0.0/16 nexthop via 192.168.1.250 nexthop via 192.168.1.251

which would then look like:

# ip r default via 192.168.1.254 dev eth0 172.16.0.0/16 nexthop via 192.168.1.250 dev eth0 weight 1 nexthop via 192.168.1.251 dev eth0 weight 1

It seems that the NetworkManager keyfile format is not able to handle that situation.

How can I configure static ECMP routes with Rocky 8/9 and NetworkManager?

Thanks,

Uwe