If the goal is to ease importing of objects, adding to uuids to acs_objects might be an option.
OTOH, if you know to import data from some satellite" system B or C into A, one can store the highest known object_id of the last sync on A (e.g. B_max, and C_max). When performing an import from e.g. B, map just the IDs higher than B_max (i.e. ignoring deletes). When the goal is a bidirectional sync, guess then there is no other way than having per "satellite" a separate acs_objects table as basis for a sync....
