The following situation takes place in open water on the Great Lakes outside of any marked channel.
A sailboat on the starboard tack is overtaking a power boat. Another sailboat on the port tack is to leeward of the others, and approaching from two points off the bow of the power boat. All vessels are on a course that will cause them to collide at the same location.
Under the inland rules which is the most priviledged vessel?
First off, let's remember that unlike the ISAF racing rules, colregs are not a "gotcha" rule system. Even ISAF rules are far less so today, obliging people to avoid collisions and be sportsmanlike.
But racing rules are helpful in how to approach these things as if you're on a protest jury. Start with the most fundamental, overriding rules and don't get lost or distracted in lesser details. In this case, I'd say begin by separating the apples from oranges: power from sail. In the situation you describe, power gives way to sail, period. So the powerboat must avoid both, and we can take it out of the equation. That leaves two sailboats.
With sailboats under the colregs, it helps a lot if you know the descending priority of basic rules under ISAF. Port-starboard (RULE 10) trumps all. Overtaking is rule 12. (Windward leeward is rule 11) It doesn't matter if starboard is overtaking port: starboard has right of way. (people forget this all the time on the race course).
Having said all that, let's remember colregs are designed to avoid collision and provide for seamanlike behaviour. Sailboats shouldn't maneuver in a way that places undue stress on the powerboat to avoid them. Racing rules also have the concept of "obstruction," in which a give-way vessel cannot do so because of it's obligations to avoid another vessel. That can come into play here, for many reasons. The powerboat might not be able to get out of the way of a sailboat promptly because one of them suddenly tacks in his path. A sailboat on port might not be able to avoid the one on starboard because of something the powerboat did. Large sailboats on starboard overtaking sailboats on port shouldn't feel entitled to plow right over them. (In racing, collision avoidance, even when you have right of way, is rule 14, and you can be disqualified even if you're in the right if you cause injury or damage.)
And just remember, if there's a collision under colregs, it's not going before a yacht club jury: it's going to end up in a civil suit and possibly with charges laid.
Over to everyone else.