show when users not availble to travel

I don't think there is a way to show this, but wanted to ask. In the resource tab, is there a way to show that a user is unavailable to travel for work? We are using the resourcing for a team of traveling consultants, and sometimes they are not able to travel to a client site (due to an illness, etc.) and we wanted to show that they can still be resourced, but not available to travel. Something like adding a comment to their resource allocation for a specific time period. Thanks!