Dear Kemal, all,
To link an existing station in OSCAR/Surface to a contact you need to edit the station concerned and add the intended contact under the "Station contacts".
The current workflow in OSCAR/Surface doesn't allow adding several stations to an existing contact at once.
This issue has now been added to the list of possible change requests for a future release of OSCAR/Surface, in case it becomes clear that it is a users requirement.
Therefore, comments and feedback from the community will be much appreciated.
Thank you and kind regards,
Luis