Found this on a quick Amazon search. I'm sure there are others as well. Dixon TCF72 Nylon Tuff-Lite Fitting, Short Shank Coupling, 3/4" GHT Female x 1/4" Hose ID Barbed: Amazon.com: Industrial & Scientific
I'd use the nylon hose clamps like this Double Gripping Nylon Hose Clamps, Snap Grip Nylon Plastic Hose Clamps (31.5-34mm (1.25inch), 12pack) - Amazon.com