The QRH OEB chapter starts with a List of Effective OEBS (LOEOEBs)
That LOEOEBs clearly identifies those OEBs that affect ECAM actions, and the OEB procedure therein will always supersede the ECAM actions and some clearly and unequivocally state to disregard the ECAM procedure (and use the following OEB procedure instead).
Our preflight SOP calls for a review of the LOEOEBs at the start of every pairing (after the preflight, before pushback) and each crewmember must advise if he is not familiar with the OEB (ECAM related or not)
At most, I think we may have had 10 OEBs in effect at once but only 3 were related to ECAM. The preflight review certainly helps at remembering them.