Cross ledger approvals functionality for Expense reports

We are implementing cross ledger approvals for all expenses.

At the moemnt we only have UK and US for expenses but we need to ensure that this is scaleable if we role out this functionality.

1.    US Ledger Employee – US Ledger Super visor = Approval possible

2.    UK Ledger Employee – UK Ledger Super visor = Approval possible

3.    US Ledger Employee – UK Ledger Super visor = ?

4.    UK Ledger Employee – US Ledger Super visor = ?

Can you please let mw know what need to do if we achive this functionality in 12.2.5.

Thanks,

Sridhar.