Need some suggestions in grouping of items

[GP]

I have a list of items:
    ShelvesToPack = [{'ShelfLength': 2278.0, 'ShelfWidth': 356.0, 'ShelfArea': 759152.0, 'ItemNames': 1},
    {'ShelfLength': 1220.0, 'ShelfWidth': 610.0, 'ShelfArea':   372100.0, 'ItemNames': 2},
    {'ShelfLength': 2310.0, 'ShelfWidth': 762.0, 'ShelfArea': 1760220.0, 'ItemNames': 3},
    {'ShelfLength': 610.0, 'ShelfWidth': 610.0,   'ShelfArea': 1450435.0, 'ItemNames': 4}]

I have a certain criteria and I  want to group the items based on those.
I need the program that tells how many minimum number of groups one can have and how the items are grouped. I would like to form groups of these items such that (sum of shelflength (of itmes) <= max length or sum of  shelfwidth (of items) <= max width) and sum of ShelfArea (of items) <= Max Area. In this case, if we look at the logic we can have all the items packed in minimum 2 groups - item 1 and 3 will form one group and item 2 & 4 will form other group. I would like to have the answer in the format:
    [[{'ShelfLength': 2278.0, 'ShelfWidth': 356.0, 'ShelfArea':    759152.0, 'ItemNames': 1} ,
     {'ShelfLength': 2310.0, 'ShelfWidth':    762.0, 'ShelfArea': 1760220.0, 'ItemNames': 3}],
    [{'ShelfLength':     1220.0, 'ShelfWidth': 610.0, 'ShelfArea':   372100.0, 'ItemNames': 2},
     , {'ShelfLength': 610.0, 'ShelfWidth': 610.0,   'ShelfArea':   1450435.0, 'ItemNames': 4}]]

I have written a code but it does only one grouping ( need some help why it doesnot for the remaining items and what corrections need to be done) . 

ShelvesToPack_sorted=sorted(ShelvesToPack, key = itemgetter('ShelfWidth'), reverse = True)
AreaOfObject= 2972897.28
current_width = 0
current_length = 0
current_area =0
shelf =[]
shelves=[]
if len(ShelvesToPack_sorted) > 0: 
       for item in ShelvesToPack_sorted:
            if (current_width + item['ShelfWidth'] <= 1219.2  or  current_length + item['ShelfLength']  <= 2438.5) and  current_area + item['ShelfArea'] <= AreaOfObject:
                shelf.append(item)
                current_width += item['ShelfWidth']
                current_length +=  item['ShelfLength']
                current_area += item['ShelfArea']
del item

if shelf: 
    shelves.append(shelf)

print(shelves)

This produces only one grouping and does not group the remaining items. 
[[{'ShelfLength': 2310.0, 'ItemNames': 3, 'ShelfArea': 1760220.0, 'ShelfWidth': 762.0}, {'ShelfLength': 2278.0, 'ItemNames': 1, 'ShelfArea': 759152.0, 'ShelfWidth': 356.0}]]

Can anyone please suggest?