Can I split expenses based on the custom fields?

Yes, that can be done.

• Go to the expense you would like to split and select Split on top of the expense details.
• Choose how you would like to split the expenses. In this case, it would be Split by field.
• By doing so, you would see all the available fields that can be used for splitting the expense.
• Select the custom field on the basis of which you would like to split.
• Make necessary changes and hit Save.