How to assign approval group for budget version based on different business unit

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Currently, I've activated approval for budget version, now my budget version able to be submitted and approved but only with same user. please guide me about how to setup budget version approval so applicable user can approve my submitted budget version.

I have 7 layers for approval with different users base on business unit.

User approval is: 

'Project Manager' then 'Cost Control Budget' then 'Hospitality Budget Control' then 'Project Director' then 'Project Director 2' then 'Director' then 'President Director'

no special condition for approval at budget version, all budget version must be approved only with different user based on business unit