BGP Metrics

Hi all,
  I've occasionally noticed a requirement to disregard mask when
determining preferred route in the BGP algorithm. Specifically, when
a multi-homed customer wishes to announce both his delegated networks
through both connections. The goal is to achieve true multi-homing,
with out requiring the customer to get independent address space. Thus
far, I've used various "miserable hacks". Has anyone else perceived a
similar requirement? if so, has anything being done to get such a flag
added?

Or am I just missing the obvious?

- --
Rusty Zickefoose | The most exciting phrase to hear in science,
rusty@cw.net | the one that heralds new discoveries, is not