Look each type of cactii up before placing in ground to make sure they take full sun....and
plant away....I am a cactophile and have at the very least 80 cactii/
succulents etc. planted in the ground!!!! Just move them out slowly to acclimate to the sunny conditions or they will burn, look bad and possibly croak. Make sure the ground has quite a bit of sand....they do not like clay soil at all. I have decomposed granite, clay, no top soil and mega hard granite soil...(if you can call it that)...In my case I just dig up the area thoroughly and incorporated quite a bit of compost/soil(no sand because I already have the crushed granite) and planted away.
So to answer your question YES by all means you can
plant in the ground!!! Remember I live in California so I am not sure what your weather is like...if it rains a lot make sure there is plenty of drainage. Also while looking up the info on full sun etc....look up how tall, wide etc. that
cactus will eventually get so you don't have to go transplanting them again...when they are over 8 feet tall and towering over you with mega sharp stickers they are not fun to move....you will have to TRUST me on that one....been there done that! Might I also suggest good gloves, and newspaper help immensely!!!
Catlover