OpenBGPd: AS path prepend for certain networks only?

[Bernd]

Hi,

running OpenBSD 5.3 (amd64) for BGP routing for more than one and a half 
years without any trouble -- thanks guys!

However, as setups evolve, new questions may arise. As far as I get from 
the man pages, it's only possible 'globally' to apply prepending to AS 
paths:

     prepend-neighbor number
             Prepend the neighbor's AS number times to the AS path.

     prepend-self number
             Prepend the local AS number times to the AS path.

I'd like to do this only for certain networks in our AS, to force 
ingress and egress traffic over a certain uplink -- leaving all other 
networks untouched by this.

Is that possible with OpenBGPd?

Thanks,

Bernd