Posting Mileage to two G/L Accounts

Hello experts,

I need help or ideas with the following requirement: customer requires users to enter mileage expenses based on which G/L account the posting should be (reimbursement is through FI-AP). There is only a single, flat-rate mileage reimbursement field in expense entry screen; is there a way to select or split this in the expense entry screen?

Here are my ideas for work around:

1. Journal Entry after posting (undesirable)

2. I am aware of cost distribution on Trip Segment tab, but this can't be used to split to G/L Accounts?

3. Create an expense type for Mileage where user would enter a whole amount

4. Create a separate trip provision variant where this is setup and assigned to user's master data

Here is the field I am talking about:

I appreciate any feedback!

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