Training puppies to run?

We have two 4 month old coon hound pups, and after clearing it with our vet I have started trying to train them to run with me (short distances, like 2/3mi). Problem is, when I have them both running, one thinks it's playtime and tries to nip at the other one and I have to stop running about every 20 seconds to split them up. Or they get so interested in the trees or geese that they get off track. Anyone know how I can train them to run with me?
 
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