question regarding table lookups

[Andrew Azarov]

Hello,

I wanted to ask bird gurus whether there is a way to lookup record in a 
different table during filtering?

We have several connections but also external policy generating daemon 
which optimizes routes.

The route optimization goes into kernel table 2 (as opposed to master).

After that we have a pipe which imports those with higher preference.

Problem is when the route is withdrawn from bgp peers partly or 
completely (basically is not available any more) the route from peer 
table still gets imported.

The result is - we have network routing to nowhere, while there might be 
alternative working routes.

I tried to find any information on another table lookup inside filter 
but was unable to discover anything meaningful...

Is there a way to either:

a) lookup another table within import filter for master table and bump 
preference?

b) during import from kernel table #2 bump preference in other tables? 
instead of using pipes

c) modify preference inside tables manually without using kernel tables? 
ie with birdc?

Thank you in advance

Regards,

Andrew