index to find duplicate names

How can I use the index feature to search column A for duplicates and return results of each row in column B from each cell in Column C

in this example Column A is where the duplicates are
and each item in the column must be unique so column B will be the unique names.
Column C is a group ID so each item in A can be a member of two groups in column C
So B will be used to create a new unique name with the group ID next to the name.

B1:B12 needs to do some thing like
=INDEX($A$1:$A$12,SMALL(IF($A$1:$A$12=$C$1:$C$12,ROW($A$1:$A$12)),ROW(1:1))-1,3)

I am just not sure how to do this

X	Column A	Column B	Column C
1	Apple	Apple, Red	Red
2	Orange		Orange
3	Banana		Yellow
4	Strawberry		Red
5	Cherry	Cherry, Red	Red
6	Apple	Apple, Green	Green
7	Lime		Green
8	Alvarado		Green
9	tomato		Orange
10	Cherry	Cherry, Black	Black
11	Plum		Purple

I have no idea what you want here

Looking at your sample, you include Orange (row 2), which appears in row 2 only, change Banana to Yellow, which appears nowhere else - likewise with strawberry/red???

Best I can come up with is this, in D1, copied down...
=IF(B2="",A2,SUBSTITUTE(B2,A2&", ",""))

I am sorry for the confusion, I don't need anything in "D" this may have been a mis-type on my part.

A and C are the constants these are filled in by the database

What I need is B filled in IF column A has a Duplicate Name

with the row item in C

in the Example above there are duplicate apples in A
so B1 would then be "Apple" from A1 and "Red: from C1 (Apple, Red)
and B6 would be "Apple" from A6 and "Green" from C6 (Apple, Green)
the Next Duplicate is A5 "Cherry" so B5 would be (Cherry, Red)
and "Cherry" from Row A10 would be B10 (Cherry, Black)