Introducing my horse to a colt?

[olympicspirit1]

So, my cousin bought a colt much to my disagreement but now I figure for the colt' sake I would help out. He has been in the pasture with the older horses ( 25+) during the day. He's doing fairly well however, he's been investigating the younger horses including my gelding, and my gelding seems very curious about him. So would it be alright to introduce him to the younger horses for a bit? It's a mixture of mares and geldings. I want to do it as safe as possible, so do I introduce each horse to him with them on a lead rope incase they try to get aggressive towards him? None of the horses are aggressive from what I seen, but I want to be on the safe side. Should I just continue to let them see each other through the fence until the colt is older?

Experience is appreciated. Thanks.