Can anyone help with conditional Value list?

Hi can anyone advise how i can make a simple value list conditional?

I have a single table on a job bag system and one field specifies the choosen print supplier i.e.: "London Print ""Wards Print" etc.

I would like the detail fields such as "Foil Colour" to be conditional because different suppliers have different references to the colour swatches.. e.g. London Print may use "RED032" where Wards Print could use "BlazeRed"

I only want to display the user the values specified by the choosen supplier..

i'm not sure where to start? I think i need to create tables and relationships but would appreciate any help thats out there on the forum... many thanks