I have two large dogs and we're pet sitting for our friend's dog who is a medium size border collie?

Our dogs are lab/dalmatian and a german shepherd/coonhound mix. We took our friend's dog over to our house so we could introduce him to our dogs on their turf (they're all neutered males) Well our dogs are doing really good. We thought they would be the ones to snap and bark at the other dog but it turns out the other dog is the one who is snapping at ours. Things are going ok so far...I mean every so often Gump will snap at Buddy and Jake but other than that they're doing really well. I guess my question is ....is the snapping every so often normal? I mean i'm pretty sure Gump feels threatened by our big dogs. I really hope they'll learn to like each other because after our friends get back in town they're going to be watching our dogs at their house. What do ya'll think? will they get used to each other? Like i said things are going really well other than the snapping on Gump's part.