Execution Outro?

[Archamedes 10]

I want to set up an outro as a lose ending where basically my squad have been captured are lined up and executed by opfor. What i need to know is how can i have my squad unarmed, in the surrender position, perfectly still and after some text on screen opfor open fire on them. Can anyone give me a detailed description on how to set this up (Triggers, on act, etc...)