Drive to each others places and don't drink. You don't need alcohol to have a good time with friends. Hang out online. Meet people who live in walking distance.

None of these options is perfect; we'd rather be able to meet exactly whom we want, and do exactly what we want when together. But the topic is socialising, not socialising in exactly the way we prefer.

Most of my friends don't live in the same city as me, so it's not easy for me either. But by one method and another I still have social contact.