No, you cannot add categories, they are built into the business logic:

Roto ID:GL0055 DLL Name: GLACGRP Account Groups

Index List - 2 Index(es)
0 - Account Group
ACCTGRPCOD
1 - Sort Order - Account Group
SORTCODE, ACCTGRPCOD

Field List - 4 fields

Name Type Size Prec Description Index Attrib Initial Value
ACCTGRPCOD String 12 0 Account Group Code 1 RKEA
Mask Presentation - %-12N
ACCTGRPDES String 60 0 Account Group Description 2 EA
SORTCODE String 12 0 Account Group Sort Code 3 EA
Mask Presentation - %-12N
GRPCOD Integer 2 0 Group Category 4 AX 0   <-------AX means it's a calculated field
List Presentation with 22 items in the list:
0 -
10 - Cash and Cash Equivalents
20 - Accounts Receivable
30 - Inventory
40 - Other Current Assets
50 - Fixed Assets
60 - Accumulated Depreciation
70 - Other Assets
80 - Accounts Payable
90 - Other Current Liabilities
100 - Long Term Liabilities
110 - Other Liabilities
120 - Share Capital
130 - Shareholders' Equity
140 - Revenue
150 - Cost of Sales
160 - Other Revenue
170 - Other Expenses
180 - Depreciation Expense
190 - Gains/Losses
200 - Interest Expense
210 - Income Taxes

No, you cannot add categories, they are built into the business logic:

Roto ID:GL0055 DLL Name: GLACGRP Account Groups

Index List - 2 Index(es)
0 - Account Group
ACCTGRPCOD
1 - Sort Order - Account Group
SORTCODE, ACCTGRPCOD

Field List - 4 fields

Name Type Size Prec Description Index Attrib Initial Value
ACCTGRPCOD String 12 0 Account Group Code 1 RKEA
Mask Presentation - %-12N
ACCTGRPDES String 60 0 Account Group Description 2 EA
SORTCODE String 12 0 Account Group Sort Code 3 EA
Mask Presentation - %-12N
GRPCOD Integer 2 0 Group Category 4 AX 0   <-------AX means it's a calculated field
List Presentation with 22 items in the list:
0 -
10 - Cash and Cash Equivalents
20 - Accounts Receivable
30 - Inventory
40 - Other Current Assets
50 - Fixed Assets
60 - Accumulated Depreciation
70 - Other Assets
80 - Accounts Payable
90 - Other Current Liabilities
100 - Long Term Liabilities
110 - Other Liabilities
120 - Share Capital
130 - Shareholders' Equity
140 - Revenue
150 - Cost of Sales
160 - Other Revenue
170 - Other Expenses
180 - Depreciation Expense
190 - Gains/Losses
200 - Interest Expense
210 - Income Taxes