ensure it is easy to create groups from an Excel or .csv file

[gdementen]

A good example is the NUTS codes from eurostat.

http://ec.europa.eu/eurostat/ramon/nomenclatures/index.cfm?TargetUrl=LST_CLS_DLD&StrNom=NUTS_33&StrLanguageCode=EN#

Maybe there is nothing specific to develop. Maybe directing users to use Pandas for that is fine, but we need at least to be able to tell users how to do it the easiest way. Currently the answer is "create the groups by hand", which is not good enough.

[alixdamman]

See point 2 in #578