I'm not sure if you can get what you need from a skill input, however you can get what you need from a Multi-Value VDN input. This is made easier if your VDNs are in a set range as i think you can only input 50 individual VDNs
Not sure if its essential, but can you confirm if you have the report designer tool ? Basically in the report design input section, select the tick box for VDN input to Multi-Value.
This will let you select the VDNs you need that relate to your skill.
Drop me a line if you need pointers on this