I want to take fields from a spreadsheet and mail merge to a listing group by one of my spreadsheet fields, as in the following example.

Group number is either Group 1-Blue or Group 2-Green or Group 3 Yellow
Item number is Unique and sequential numbers are 1-99
When the Group number changes I would like a page break
Result after mail merge:

Group 1-Blue
Item number 1
Item number 2
Item number 9
etc.
Group 2-Green
Item number 5
Item number 7
Item number 12
etc.
Group 3-Yellow
Item number 15
Item number 60
Item number 99
etc.

Where etc. are the other random item numbers

How can I do this?