filter interface in protocol device

[Alexei Gradinari]

Hello,

How can I filter scanning interfaces in protocol device?

I'd like to have something like this
protocol device {
    scan time 10;
    interface "eth*";
}       

I need it because my server acts as PPPoE concentrator and BGP router.
I don't want bird to scan ppp* interfaces.

Regards,
Alexei