How do I concatenate rows in ms access using VB.NET

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VB

MS-Access

I have a table like this and i want to convert it in such a way that the operations with same opration type,Machine and attatchment should concatenate ad their SAM will be added:

Oprn_ID	Operation_Type	Operation_Name	Machine_Type	Attatchment	SAM
1	Bottom Fold	A	SNLS	NO	1.2
2	Baby Overlock	B	5TOLK	NO	0.8
3	Gathering	C	SNLS	1/16 Folder	0.6
4	Panel Attach	D	SNLS	NO	0.9
5	Panel Attach	E	SNLS	NO	0.5
6	Overlock	F	5TOLK	NO	0.7
7	Pin Stitch	G	SNLS	NO	0.9
8	Elastic Finish	H	SNLS	1/16 folder	0.85
9	Bottom Fold	I	SNLS	NO	0.42
10	Gathering	J	SNLS	1/16 Folder	0.78
11	Panel Attach	K	SNLS	NO	0.56
12	Attachment	L	SNLS	NO	0.14
13	Elastic Finish	M	SNLS	NO	0.96
14	Overlock	N	5TOLK	NO	0.76

like this

Operation_Type	Operation_Name	Machine_Type	Attatchment	SAM
Bottom Fold	A + I	SNLS	NO	1.62
Gathering	C + J	SNLS	1/16 Folder	1.38
Baby Overlock	B	5TOLK	NO	0.8
Panel Attach	D + E + K	SNLS	NO	1.96
Overlock	F + N	5TOLK	NO	1.46
Pin Stitch	G	SNLS	NO	0.9
Elastic Finish	H	SNLS	1/16 folder	0.85
Attachment	L	SNLS	NO	0.14
Elastic Finish	M	SNLS	NO	0.96

What I have tried:

I dont have any idea to do this