I am of the understanding that 'Weapon Focus: Touch' works for both ranged and melee touch attacks.
I want to know if there is a Fighter weapon group that too applies to them? Would it be close?
you got it a bit wrong.
you can take feats for specific attacks, such as rays or specific abilities (kinatic blast, mystic bolts etc) i didn't find anywhere that you can group them in a general 'touch' attacks as focus (or specialization etc).
I believe you need to specify the ability that uses that. in case of touch maybe 'charged touch spells' can be grouped together, but then stuff like anti-paladin touch of corruption etc won't be in there, the same way as picking 'rays' work (ray of frost is in, snowball out for example). It's up to GM.
But it is clear you can't take both ranged touch and melee touch in the same feat.
see the following FAQ:
and 3, last one has this called out:
"...
Certain special abilities (for instance rays, kinetic blasts, and mystic bolts) can specifically be selected with feats like Weapon Focus and Improved Critical. They still aren’t considered a type of weapon for other rules; they are not part of any weapon group and don’t qualify for the effects of fighter weapon training, warpriest sacred weapon, magus arcane pool, paladin divine bond, or any other such ability.
..."
There's also another issue here: Not everything is in a weapon group! The list of weapons in a weapon group is exclusive, and a weapon not on any list can't benefit from Weapon Training.
the archive usually try to list the weapon's group in it's info page. even for those who missed out on the fighter's page.
and like any other exclusive club. while some are left out. others get in with triplite invitations...
really?! both light AND heavy blades (and thrown, but meh), you have no idea what you did to 2 weapon\finesse fighters out there, did you?.