Is there clubs out here who do 3 gun?

It's required for Cowboys.  Also, LIFE hosts an annual 3-gun competition, but that is for LIFE instructors only. 

Is there clubs out here who do 3 gun?

Are you talking about the 3-gun events that you see on The Outdoor Channel, where the shooters transition between handgun, rifle and shotgun in a given stage?  If so, I don't believe there are clubs on Oahu that do that.  There are ISPC clubs that have rifle and shotgun side matches, but they consist of a complete shooting stage with just the rifle or shotgun (no transition to or from handgun). 

3 gun matches that I've seen require a LOT of land, with rifle shots often in the 200-300 yard range and beyond.  Maybe there could be range facilities on the outer islands large enough to host something like that, but not on Oahu. 

Not 3 gun, but I think HPS has a multi-gun match scheduled later in the year and MPPL had a 2-gun match earlier this year. 

i've seen videos on youtube where the shooters were shooting at what looked to be 25-30 yards max

Are you talking about the 3-gun events that you see on The Outdoor Channel, where the shooters transition between handgun, rifle and shotgun in a given stage?  If so, I don't believe there are clubs on Oahu that do that.  There are ISPC clubs that have rifle and shotgun side matches, but they consist of a complete shooting stage with just the rifle or shotgun (no transition to or from handgun). 

3 gun matches that I've seen require a LOT of land, with rifle shots often in the 200-300 yard range and beyond.  Maybe there could be range facilities on the outer islands large enough to host something like that, but not on Oahu.