I'm not sure why you are wanting to do that but the short answer is no.  You're ISP is providing you with a single IP address for your WAN and your router is terminating that IP address and then creating a Local Area Network and assigning private IP addresses to your local devices.  If you try to split your WAN connection you will need a switch, second router, and second IP address from your ISP.  This gets to be business grade connections and a lot more money.  Also not necessary.  Why do you want to be before the router.  You have ZERO perimeter security by doing that.

I have done what you are wanting before when the bank I worked for needed multiple IP address for VPN connections but only needed the bandwidth of one connection.  We were assigned multiple IP address and used a switch on the WAN connection and then went from the switch to two separate routers that each terminated VPN connections.  It was stupid and not necessary except a service provider required we use certain hardware that was dedicated to them.