You certainly can make a VPS part of a VPN, if that's what you meant. As to what you need, there are dozens, probably scores, of ways of setting up a VPN. Ipsec might be the best, from a technical standpoint, but I'd be fairly surprised if many (any?) VPS kernels supported it. You might have to go with PPTP-over-SSH, which is also easier to setup. "Easier" being a relative term, here - if you've never done either before, the difference is somewhat like that between riding a seatless bicycle while naked, and riding a seatless bicycle while wearing only a shirt and shoes.
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