Bridge won't get DHCP address if network available AFTER boot

I have 2 ethernet ports bridged as follows (/etc/network/interfaces.d/br0):

auto br0
iface br0 inet dhcp
        bridge_ports enp1s0 enp2s0
        bridge_fd 0
        bridge_waitport 0
        bridge_stp off

auto br0:1
iface br0:1 inet static
        address 169.254.10.50
        netmask 255.255.255.0

In this instance, a PC and router are always in a combined unit. The router has DHCP enabled, but takes longer to boot than the PC. enp1s0 is in LAN port of the router, enp2s0 is connected to another device that will ALWAYS have an IP address of 169.254.10.49. When the combined unit is rebooted, if the router does not finish its boot process before the PC has booted, br0 will never be assigned an IP address. What I need to happen, ideally, is that at any point after the system has booted, if a DHCP server is available, br0 will be assigned an IP address. Can I configure the bridge to get an IP address after the DHCP server becomes available?