When tried to do the import, there is no option to map the currency under the Item Vendors folder.
Upon further checking, we found an enhancement request that has been logged to address this under Issue 237922 CSV Import > Inventory Items > Not able to map the Currency field under the Vendors sublist when Multi-Currency Vendors feature is enabled. However, an alternate solution has been documented to address this concern.
Listed below are the steps:
1. Manually edit the item records, or;
2. To upload the Vendor Purchase Price for currency other than the Primary, user can do the following:
a. Navigate to Vendor > Financial > Item > Import Price List.
b. For the Upload File that you will use, allot a column for Schedule (leave it blank if there is no schedule) so that the system will take your specified Currency. As per testing, if you do not allot a column for schedule (blank column), the system will think that you are uploading the Purchase Price for the Vendor Primary Currency even if the Upload file specify a different Currency.
Note: This might be tedious as this upload has to be done per vendor; however, it would allow the user to upload for vendor purchase price (multiple currencies) at a time.