I love my friends from my hometown, and I love my friends from my college as well. Although it is great having double the friends as I did this time last year, it's also a struggle sometimes!
I did not move far away in order to go to college, but I still definitely feel the distance. It was difficult, especially at first, to keep in touch with my friends from high school. As I approach the end of my first year of college, I find myself looking back at how I managed to do it.
First and foremost, be sure to visit your old friends (or have them visit you!) as much as you can. The farther the distance, the more difficult this will be, but it's almost always possible, especially during breaks. Even when you can't visit them, try to voice or video call each other. Texting is fun, but most of the time, it isn't as personal as calls are.
That's not to say that friendships can't be maintained solely through text, but it is much harder. Plus, you'll probably want to hear/see your friend anyway, which can only be achieved through calling.
Of course, you don't want to be so absorbed in your old friendships that you refuse to make new ones, or you do make new ones, but then lose them. Perhaps you could try setting some time aside for each "group," and of course, try to get both groups to meet up and talk at some point if everyone is comfortable and able to do so!
Most of my old friends from high school are also huge fans of my new friends from college and vice versa! Maybe you could invite an old pal up to your school for a weekend, and introduce them to all of the new people that you've met.
Regardless of how you choose to do it, it is always possible and always worth it to keep old and new friendships alive at the same time.