Pre Approved Misc transactions accounts generation

Dear Experts,

We have a requirement to generate Dr and Cr for project preapproved misc transactions based on below logic:

1) If capital class type of project then derieve all segment in our COA based on project classifications setup as all costs booked against fied accounts, as per business, so fine to simply from setup at project level.

2) If we try to book an expenditure against an Indirect/contract (non-capex), type of project, then we need to allow users to choose from a range of codes for majority of the segments in our COA structure. to deal with this, which is best solution? as user dont want to have manual maintenance of these codes which need to entered manually for majority of segments by expenditure type mapping etc.,