If you're talking about copper or fiber ethernet, then a manager Layer2+ switch with the appropriate uplink.
You probably have a business grade connection, so you probably need some sort of router in there. You could build a fairly simple PFSense firewall/router, but you'd need to know how to configure and manage it and you'd probably at least want some server grade hardware, which is still under $1k to build for a 1Gb router.
Then hook the router into the Layer2 switch and configure your vLANs to talk to the router.
You'll definitely want someone who knows what they're doing.