multiple client istances for openvpn connections
Solution 1:
Debian-based systems should be able handle multiple VPN connections just fine. Just put the configs in /etc/openvpn/*.conf. If you haven't modified your /etc/default/openfile then the startup scripts will startup an instance of openvpn for each *.conf in this directory.
Of course this assumes that your various VPNs don't have conflicting routes or configuration that prevent each other from starting properly.