Get the Imperial Assault Campaign module for Vassal from http://www.vassalengine.org/wiki/Module:Star_Wars:_Imperial_Assault
The next total solar eclipse holiday in 2017 in the USA.
Technically, you're doing one first, so the next one would not be at the very start of activation. Or are they actually being done at the same time and therefore, both in line with the required timing?
Abilities with the same trigger do not 'advance time' in the game. When you perform an ability with trigger X, it is still X after you have resolved the ability and can choose to resolve another ability with timing X, or skip it. (All abilities with costs are voluntary.)
This happens all the time during attacks with a host of different abilities. The same timing rules (page 2 of the RRG and quoted in the thread below) apply to all abilities.
Ability Resolution order during attacks