Hi Matt,
Unfortunately, AtoM does not currently have the ability to attach digital objects to accession records. This would require development to be able to add to AtoM.
In 2016 Artefactual prepared estimates for an institution interested in being able to attach multiple digital objects to an accession - you wouldn't get a preview generated like a digital object attached to a description, but you could upload multiple and see them in a table-based view, with a description field associated so you could leave a short not on what each attachment contains - as well as a way to delete them. At the time, our estimates for adding this to AtoM were around $14,500. We would reserve the right to revise these estimates should anyone wish to sponsor this work now for inclusion in a future release, but that should at least give you a ballpark sense of what we think the work would cost.
I will say that, now that the Canadian Archival Accession Information Standard (
CAAIS - the first national standard for describing accession records) has been formally released, there is growing interest in the Canadian archival community to see AtoM's accession module overhauled to implement support for this. So far this is just general interest and nothing concrete yet - and it will be a big job, likely requiring several institutions to collaborate to sponsor its implementation.
I personally think it is a very good standard that covers the vast majority of features I hear AtoM users asking for in the accessions module - including this. Section 4.5 of CAAIS is devoted to external documentation, meaning that for AtoM to implement the standard we'd need to add a way to upload multiple attachments.
In the meantime, you might consider simply using one of the existing fields to capture information on where the related agreement is stored locally in your institution.
Regards,