Two questions related to each other -

1. On the standard event  edit page how can I add a custom button or custom link ? I know this can be done using visual force, I need to know how to do this on the standard edit page.

2. Under the Contacts/Attendee Info, when you try to add contacts to the event, it opens up a new page . My requirement is to show only the contacts tied to the Account  on the Available Selected List ( to avoid picking wrong contacts). How do I go about doing this ?

The solution I came up for question 2 is this - Create a new custom button and place it on the detail page. When clicked, it opens up a visual force page which displays the contacts tied to the account. It then mimicks the default Salesforce behaviour of adding /removing the contacts, adding /deleting the EventRelation objects.

   If question 2 is not do-able then is the solution I came up with good ?

Thanks and hope to hear from the architects as well.