Writing to a campaign member field on import (SFDC)

Question:

Is it possible to write to a field on the Campaign Member Detail within SFDC when importing leads?

Example:

Tradeshow booth leads are gathered with notes/comments detailing the conversations (Requested a demo, wants contact next budget period, had an encounter with Bruce Springsteen, etc). These notes are directly related to this tradeshow campaign, so it makes the most sense to upload them to the campaign member detail (where we have a comments field) rather than directly to the lead record where they will be overwritten every time there is a new note/comment.

It appears that Marketo can only update the lead/contact record when importing members. It is able to write to the campaign record though, because it changes campaign member status on that record. So... is it possible to write to a field on the Campaign Member Detail within SFDC when importing leads?

Cheers,

Ryan