Though Skype doesn’t have a specific individual status you can configure for individual users or groups, there is indeed something you can do to appear with an offline status to someone while staying signed in to skype and being online for the rest of your contacts.
How to appear with an offline status to an individual status or group in Skype?
- Right Click on the contact or group and check block, this way you will show as offline permanently. You can unblock them later without the need of deleting the user.