The Acropolis - Market Square with Trinity Soldiers

There are 6 Trinity soldiers in this area, 3 directly in front of you and 3 more on the far right side of the square. If you don't want to engage them all at once, stay hidden in the bushes for now and wait for one of the first 3 men to wander off to the left.

Once he's separated from the others (yellow instead of red in Survival Instinct view), you should be able to kill him with a silent headshot without the others noticing.

Then shoot an arrow into one of the columns off to the left. This should cause a second man to go investigate.

As soon as he's far enough away from the squad leader...

...kill him with another headshot.

Dispatch the leader the same way.

Now move around to the far left corner, taking cover behind various barrels, boxes, and low walls...

...

...until you come to a large opening in the stone wall, through which you can see the 3 remaining enemies.

Wait here for a bit, and they should split up without your having to do anything.

As the first of them comes toward you, try to shoot him in the head before he can sound the alarm.

Then take out the one in middle while he's on his own.

Finally, move to the right...

...to get a clear shot at the last man. Stealth isn't really necessary at this point, but a headshot only takes one arrow or bullet.

Also, if you've unlocked the Finesse Hunter skill, chaining 6 stealth kills like this results in a sweet XP bonus.