Is there a way to restrict pending worker conversion based on Pre-boarding journey completion?

Summary:

The business requirement is that they want a solution so that while converting a pending worker a check is there like a DFF 'Preboarding completed' with the values 'Yes' which should only populate in the dropdown if the pending worker has completed their Pre-boarding journey, otherwise the no value should be in DFFs dropdown.
Is this feasible? If not then are there any alternatives to acheive pending worker conversion restriction.

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