How to use 3rd party bridge for network?

I have a bridge interface create as part of 3rdparty virtual lan application prerequisite.
I’m trying to add lxc instance under that bridge so it can communicate in them.
I added that bridge as parental in physic network.
However when I assign the network to a lxc, the instance failed to start.
From lxc log, the lxc trys to move the entire bridge to another namespace,which would fail no doubt since its owned by the application.
This is somewhat misleading since mostly we expected incus to create a virtual interface under the bridge instead of take the whole.
I recommend to reconsider the behavior for such usage.
Also in the meantime,is there workaroud for this?
Probaby we can just precreate some virtual interface under the bridge and let lxc use it as physic interface,but i don’t which interface type to use.

lxc tri 20250118183105.391 ERROR    network - ../src/lxc/network.c:lxc_network_move_created_netdev_priv:3590 - 无效的参数 - Failed to move network device "bridge_t" with ifindex 6 to network namespace 75526 and rename to physs6e6aB
lxc tri 20250118183105.391 ERROR    start - ../src/lxc/start.c:lxc_spawn:1847 - Failed to create the network
lxc tri 20250118183105.412 ERROR    lxccontainer - ../src/lxc/lxccontainer.c:wait_on_daemonized_start:837 - Received container state "ABORTING" instead of "RUNNING"
lxc tri 20250118183105.412 ERROR    start - ../src/lxc/start.c:__lxc_start:2114 - Failed to spawn container "tri"
lxc tri 20250118183105.412 WARN     start - ../src/lxc/start.c:lxc_abort:1037 - 没有那个进程 - Failed to send SIGKILL via pidfd 17 for process 75526
lxc 20250118183105.598 ERROR    af_unix - ../src/lxc/af_unix.c:lxc_abstract_unix_recv_fds_iov:218 - 连接被对方重置 - Failed to receive response
lxc 20250118183105.599 ERROR    commands - ../src/lxc/commands.c:lxc_cmd_rsp_recv_fds:128 - Failed to receive file descriptors for command "get_init_pid"

Probably it’s better to add another network type for such usage since a normal bridge can be moved to another namespace.
And there exsits corresponding usages for both cases.

Apparently it can be down from cmdline, but not from webui.
The default mode that webui create takes the whole interface