Hi Greg,
Actually this is a common situation with Account Based Marketing where the focus is on sourcing and collecting together a group of contacts at an account and then marketing to them together to generate opportunities that eventually close. So if your business is targeting specific accounts (industry, infrastructure, etc) vs. mass marketing (we'll sell to anyone) I'd suggest:
1) Move all the contacts at the same company into an account so they're all in one place. Assign contacts to accounts and convert leads that come in into contacts at those accounts as well.
2) Consider setting up a 'contact stage' field for the SDRs to track their engagement with each contact to be able to see who's been contacted, who's engaged, etc. You'll be able to see who in the account is engaging (researcher, champion, etc) and who may need to be nurtured to keep them involved or at least up to date on your activities at their account.
3) As qualifiing contacts occur, create and then add them to an opportunity so that you can track who's associated with the opportunity as well as the campaigns that influenced their joining the opportunity or moving it forward.
4) Of course then track the closing of the opportunity to then attribute back to the contact, the SDR and the Marketo campaigns.
So not all that different that classic mass marketing (lead to contact-opportunity-close) you just are shifting the qualification effort into the contact/account domain vs. leads.
Hope that helps.
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