Methods for phage separation
Look up "phage purification." Basically, you add your phage solution on top of your host bacteria on a plate and incubate. As the bacteria grow, you should see plaques (clear areas in the bacterial lawn). Each plaque should be the progeny of one original phage, although sometimes two or more phages could be very close to each other on the plate and it will look like one plaque. So you have to take a sample of a plaque, re-plate on another lawn of host bacterium, and repeat this process for several rounds until the plaque morphology seems to indicate that there is only one type of phage present. Here is a good resource for phage protocols: http://phagesdb.org/workflow/