I posted this answer in dog health as well but here it is again. For future references please only post it in one area & I thing this fits better under dog general than health.

Hopefully you did not post pics or descriptions of them on the posters as that is a big no no for finding owners for lost pets. Otherwise anybody & their brother could claim the dog as they know everything about it already.

It makes it really easy to do if you did not do that, just have the owner describe what they look like, how old they are, the sex of the pups. If the pups are old enough to know a name ask for the names & see if the pups respond to the name.
Ask where they may have gooten loose at, & is it anywhere near where you found them or where they were spotted at?
Ask what the pups favorite toy or treat is, ask what commands the pup know. If the pups are pretty young ask if the owner has the parent(s) to the pups & what breed it is. Ask what they planned on doing w/ the pups (are they keeping them.. finding homes for them etc..)
It should be pretty obvious after that.
If nothing else works just explain to each one your dilema that 4 people have claimed them & you know that the pups can not be from 4 diferent owners. You need to re-search to make sure the pups go to their real home. Any good pet owner will understand.

Any pics??
they sound like cuties!