Item group? Customer group?

[blackfriday]

@Tanuj

Your custom DocType is going to be the hardest part. Like @max_morais_dmm suggested, you can have three parts, where Part A will mostly be linked to your Customer under CRM module (These needs to be mapped via custom scripts under Settings>Customize).

Custom scripts? I am still confuse where to start, and even to start I have to know custom scripts? This sounds so not friendly.