The question as to whether an item should belong in the station add-on list or in the group add-on will depend on one or two factors:
1) Does the item require a vendor invoice to be created then use Add-ons
2) Are there different defaults for each customer then use Add-ons
3) If the option is consistent for many stations then use the Group options
4) Mark ups are normally a group option
Normally S2k will set these up as this requires expert knowledge of S2k and is normally not often unless you are adding stations each and every week, in which case we will teach on this option, otherwise contact us for assistance.