And what's that comment about getting COM missions so there'd be more ships to "defend" a station?
Basically it's just droping your own COM mission on top of theirs. So if say they have a hijacking mission with 3 ships of 400k power total to beat and their ship has 700k power then they won't really have a hard time. However if you have a hijacking mission at the same planetary body then you can "drop" that mission by talking to the crew in your cargo bay and then those ships will pop up in orbit as well. Because they are both hijackings the game will then add them to the same force basically and instead of that person having to take down those 3 ships with 400k power they will then also have to take down whatever ships have popped up from your hijacking mission. It can be extremely annoying and if a larger player were to drop a COM mission on top of a smaller players mission it basically could be used to simply block their mission and make it impossible for them to complete. Of note though only missions of the same type interfere with each other, if someone is doing a nest mission (pretty obvious because there will be a pirate station in orbit) and you drop a hijacking then they won't have to deal with the pirate ships that pop up to complete their nest mission and you won't have to deal with theirs.
At least that is what I remember being told quite some time ago, I'm not that experienced in dealing with multiple missions at once but I'm pretty sure that is how it works. Sargas had to remind me of this not too long ago as I had just come back to the game after about a 9 month absense and I thought him dropping one of his missions had lengthened my timer but I had just miscalculated when it would be finished. That is another way to use COM missions, just dropping yours on top of theirs to lengthen their timer thus their ship has to remain in orbit longer than they thought and it gives you time to attack their ship (if that is something you like to do).