Custom button to Update record and Copy to new record

[Empowering]

I have a custom button in calendar details that copies the current record to a new record entry form and passes all the parameters so it's essentially copying the original appointment.  The user can then make changes to the new appointment and submit it.  Right now, if a user makes any changes to the existing appointment, they have to click Submit (we renamed it to Save Changes) and then go back into that detail record and click the custom Copy to New Appointment button.  I need them to be able to click just one button "Save Changes and Copy to New Appointment".   Here's what I have now for the custom button (modified the url, as it's internal only):

<input onclick="location.href='https://theurl.caspio.com/dp/001112200112?Impl_org_Users_EmployeeNumber=[@field:impl_Calendar_EmployeeNumber]&amp;Impl_Calendar_CRM_ID=[@field:impl_Calendar_CRM_ID]&amp;impl_Calendar_DayTypeID=[@field:impl_Calendar_DayTypeID]&amp;impl_Calendar_Location=[@field:impl_Calendar_Location]&amp;impl_Calendar_Topics=[@field:impl_Calendar_Topics]';" type="button" value="Copy Appointment" />

[ChrisCarlson]

I would recommend using a trigger to achieve this.

[Empowering]

Can I run the trigger only when that button is clicked?  I still need the normal Update button to just update the record, then I have another one that should update the record and copy it to the new one, and yet another that copies it to a different resource (transposes a few of the fields from the original record on the new one) and should update the current record first.  It's not every time a record is updated that these things happen.  

[Empowering]

Any more ideas?