Multiple physical ports for one LAN zone

I thought bridging was for joining multiple networks. I don't get any connectivity on the additional ports when I use bridging. Here's a screenshot of the config before setting up the bridge:

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And this is after:

Plugged into eth1, everything works great before (obviously) and after setting up the bridge. I can't even ping the gateway (192.168.1.1) when connected to eth2 or eth3. Am I doing something wrong?