Any event triggered when deletion happens

Hi guys,

I wonder is there any way how to handle following scenario:

We have custom BO which has association to Activity BO.

User deletes Activity's instance and here I want that my custom BO's instance would be deleted together with this activity, as we have 1:1 relationship between Activity BO and mine custom BO.

As I know, than none of events on activity could be triggered when row from Activity's OWL is removed, right? As possible work around I see MDR usage on my custom BO, but it won't be real time check if my custom BO instance still has association to activity. So another thought what I had, but I couldn't find the way how to get it working, is there any chance to trigger on my custom BOs OWL any actions (mass enabled action which checks if my instances has set association to activity)?

Thanks,

Uldis