We need a groups model which supports List<?>, all the Groups models use arrays

As title, we have no groups model which supports the use of lists. Using multidimensional arrays to accept data is not good.

I have attached a sample, this is just a straight copy of SimpleGroupsModel without clone functionality which takes in lists instead of arrays (the list is live). My code is just an example, other functionality needs to be added to bring it in line with our other models, such as the ability to have a live list etc. etc.

Thanks.