Hi Becky,
In Numbers, a Sheet is a large blank canvas, on which may be placed several types of objects, such as Tables, Shapes, Text boxes, Charts and images.
Your "Master List" is contained in a Table, and is probably on Sheet 1 of the Spreadsheet, a name which refers to the whole Spreadsheet Document.
New Sheets are created by clicking the + at the left end of the set of tabs (containing the names of the existing Sheets),
When created, a new Sheet contains a single Table, named "Table 1", and containing no data.
So, no, you can't "create a SHEET from a Category Group," but you can 'create a Sheet containing a Table containing data from a Category Group.'
Data can be copied from a specific category on your "Master List" table using an Index column constructed on that table to a "Group List" table on the same Sheet or on a separate Sheet, using a lookup formula that searches the index column and returns the data from a cell on the indexed row to a cell in the equivalent column on the Group List table.
Specifics require specifications.
Which columns of the Master list do you want to copy to the Group list?
Which column of Master contains the Group names?
How many Header rows have been defined?
Regards,
Barry
PS: If you are using the current version of Numbers (6.1 at this writing), try the Smart Categories feature.
Using Smart categories, you should be able to group the rows of your Master table into categories, Copy the cells in a specific category, then paste these into a new Table, to which you may have to enter the header label manually.
Not particularly 'dynamic', but might be a workable solution.
The new table won't update automatically, but the Categories (and their contents) work with the current state of the Master table, and are always 'up to date' when applied.
B.