My current solution for dedicate internet link for specific applications (eg. skype) is to use PBR with static destination of Skype servers IP addresses.
But unfortunately IP address may change/add, and we have to manually configure them in PBR. So I want to think for another way to do this solution. One I can think of is to use some DPI marking DSCP and have routers to do PBR by DSCP marked. But I am still not sure if it will accurate enough.