Custom Archive Tables

Is it possible or considered bad practice to create custom archive tables (e.g. archive_numeric_organization_2011_08)?

We track our users by organization and want to archive visits, actions, etc. per organization. I figure it will save some space if we store that information in a table where each key is simply the organization ID, rather than having thousands of “organization_{id}” entries in the regular archive_numeric tables mixed in with all the other entries (e.g. done, nb_visits, etc).

I not interesed … :S