how to send the Gruped rows of gridview to next on button

Question

when user select the 1st 2 rows which are checked on clicking the button i am sending to next page .but on sending to next Page only the yellow colors rows are selected can you Please help me in sending the two rows which are under one group to next Page

checkbox	AsnNumber	BolNumber	Linenumber	qty	UAM
checked	ASN1	ASN1	0010	1	EA
			0020	1	EA
Cheked	ASN2	ASN2	0010	1	EA
			0020	1	EA
Unchedked	ASN3	ASN3	0010	1	EA
			0020	1	EA

I have grid view rows which are grouped as shown in below diagram