Amount limit require in USD at Approval Group

Hi

We are doing a roll out project. Please find the below client requirements.

1. Client had already USA OU.

2. Would like to create another LE and OU for NL under the same Business Group. 

3. Client require approval limit should be in USD for NL OU which functional currency is EUR.

4. Client using supervisory hierarchy.

I suggested them we can enter near to the USD (conversion amount) in approval limits, but they are not satisfied.

Please help me out is there any way to achieve client requirement. 

Regards, eswar