you track divisions by class after you enable them in preferences and set up a class per division in the class list.  Then you track income and expense by tagging the transaction or the line item with the division class

only in enterprise can you assign a class to an account

you […]

Resolution for 'assign expense accounts issue: 'Better phrasing of question: how to assign expense accounts by “division”?' available: Yes.

The assign expense accounts issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the assign expense accounts issue yourself by looking for a resolution described in the article. If it is a complex assign expense accounts issue or you are unable to solve the issue, you may contact us by clicking here or by using other assign expense accounts support options.

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