Ok, this one is a little tricky.

While playing Diplomacy I had several scouts of the empire I was thinking of setting up a diplomatic relation with flying around heavily defended systems under my control.  As I pressed 'Cease Fire' option most of my defences had shot and destroyed his scouts and ships that were in my space - since the AI does not respond to the cease fire straight away is it possible to stop all auto targeting of said empire when you press the cease fire option.

The reason for my asking is that it would be a near impossible feat of micro-management to turn off all my defences manually while trying to set up a cease fire and then turn them back on again to attack the empires your at war with.

It also makes it very difficult for them to forgive you after blasting a small fleet away by over keen defences.