I think we do not have the functionality to extend a chart of accounts. So if you want to reuse the IFRS chart of account in your country code you should have to copy paste all the definition of the account_ifrs module into the account_pa module. Otherwise activating the account_pa module will force any user of the IFRS chart to load the panama accounts which is not correct for other countries.
If we go this way probably we should think on how to improve this situatoin.