Share VPN connection and normal internet with mobile device over WIFI

Question

I have a PC and Mac that I have running on a VPN for work. The VPN is only required for traffic to a sepecific set of servers (not all my internet traffic is routed over the VPN). The vpn is made (on both devices) through the ethernet connection. I have some iOS and Android devices that I want to share this connection with.

I've tried setting the VPN connections up on them directly, but it seems that I can never get the setup working correctly - either they attempt to route all traffic through the VPN (and I can't access the internet in general, just the 'VPN secured' servers) or the internet works fine but the servers behind the VPN are unreachable (even though I'm connected). I'm working on software that needs access to both the internet in general and the VPN-secured servers at the same time.

I was wondering if there was some way for me to basically setup something on my PC (either my mac or Windows7 PC) and have the mobile device connect to that and basically share my connection verbatim from that device (e.g. have the PC/Mac act as the man in the middle to forward all the traffic to the appropriate place, as if a program on the computer was making the request). I've tried setting up internet sharing from my Mac (sharing the VPN connection) and then having the mobile devices connect through that but it seems to be sending ALL traffic through the VPN.

I've also tried setting up the VPN connection on my router (which as DD-WRT installed), but wasn't able to get it to connect to the workplace VPN correctly.

I'm a VPN beginner, so please bear with me.