Obi and Qui-Gon vs Maul. Episode 1
Obi and Ani vs Dooku. Episode 2
Palpatine vs Windu, Kit Fisto and 1 or 2 more Jedi. Episode 3 XDD
These are all examples of two-on-one scenarios. The last one with Sidious doesn't count, since he kills 2 or 3 Jedi before the fight even begins, so it's basically him vs. Mace Windu.
A group of 5+ PCs are going to chew through a single opponent in a couple of rounds, unless you're prepared to go "full retard" with his stats. We're talking 10 soak, 30+ WT and a minimum of 10 ranks in Durable. The only alternatives that I can see is that you'll need to either stack the environment very much in the NPCs favour or throw in some henchment; either a few rivals to pose an additional threat to the players and thereby divert their fire from the main NPC, or some minions to go with the squad rules and act as meat shield.