Is it possible to set the SRC-Attribute on routes that will be inserted to kernel?

I have private /31 networks to connect to other routers in my network and i don't want to see these private ip-addesses on a traceroute from a network with public ips. Every Router have a public IP-Address on his Loopback-Interface, so i can use that address for ICMP-Replies.

Lets say 78.22.45.0/24 and 78.22.46.0/24 is my public network address space.

router#1.lo = 78.22.46.1/32

router#1.eth1 = 10.0.0.1/31

 ----- eBGP -----

router#2.eth1 = 10.0.0.2/31

router#2.eth2 = 78.22.45.1/24

router#1.lo = 78.22.46.2/32

On traceroutes i like to reply from a specific ip-address. In case of router#1 with 78.22.46.1 and for router#2 with 78.22.46.2

On Unix / Linux you can accomplish that feature with

router#1# ip route add 78.22.45.0/24 via 10.0.0.2 src 78.22.46.1

So how can i set "src" with bird on import route filtering process?