```
set interfaces bridge br10 member interface eth1
set interfaces bridge br20 member interface eth1
commit
```
Checking the interface assignemnts:
```
# ip link show dev br20
242: br20: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
link/ether 62:34:3a:8a:fe:49 brd ff:ff:ff:ff:ff:ff
[edit]
# ip link show dev eth1
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master br20 state UP mode DEFAULT group default qlen 1000
link/ether 00:50:56:b3:cd:ba brd ff:ff:ff:ff:ff:ff
altname enp0s19
altname ens19
```
The later addition wins and the CLI reports `br10` would have `eth1` as member, but only `br20` has eth1 as member - as a member interface can not be used multiple times.