Concatenate a column based on a column with matching rows

[excelsior51]

a b c d e g h
1019 1 John doe Water Sal 61-01547-9152 40
1090 1 John doe Coop WAR 63-00597-000 2.57
1091 1 Chocolate Coop WAR 63-01729-000 5.12
1091 1 Chocolate Coop WAR 63-01990-000 68.178
1091 2 Chocolate Coop WAR 63-01728-000 0.312
1091 2 Chocolate Coop WAR 63-01730-000 2.02
1092 1 Flower Cofe Moon 63-02014-000 5.5
1126 1 Flower East Cow 27-02619-010 6.6


So I'm trying to concatenate based on column A. Everything row in that column that is matching I would like to concatenate column G into the first origin of that matching row. Poorly explained I know, but for instance:

Rows a3-6 match and ideally I would like them to look like.

1091 1 Chocolate Coop WAR 63-01729-000, 63-01990-000, 63-01728-000, 63-01730-000 5.12
1091 1 Chocolate Coop WAR 68.178
1091 2 Chocolate Coop WAR 0.312
1091 2 Chocolate Coop WAR 2.02

Not sure if that is even possible. Any help would be greatly appreciated!

[duffry]

Doesn't look like a standard function will sort it (prepared to be shown I'm wrong here) but this may help:
http://www.cpearson.com/excel/stringconcatenation.aspx