I am not sure if I understand what you mean by deleting of the custom events. If you are looking at a particular individual, under options, you select either to add a new event/attribute or remove an event/attribute. You can also create a new event/attribute as well.

You could use PAF Insight which allows you to view two different files and pick and choose what you want to merge into your current file. Using this will allow you to look at each individual side by side and decide which events you want to add to your file. Most Family History Centers have PAF Insight that you could use.