Correct currency in Google Analytics

Site URL: https://www.foryouth.co

Hi,

I'm running 4 country-specific shops on one domain (with subdomains), each in their own different currency.

I have one Google Analytics account in a single currency (SGD, Singapore Dollar). When there's on order on the Malaysian site in MYR (Malaysian Ringgit), the amount gets shown in Google Analytics in the "native" amount and it doesn't get converted to SGD. As the MYR is 3x the value of SGD, this obviously ruins the e-commerce data in Google Analytics. There's a tool called Hitbuilder with which I can edit the currency (https://ga-dev-tools.web.app/hit-builder/?v=1&tid=UA-XXXXX-Y&cid=555&t=transaction&ti=12345&ta=westernWear&tr=50.00&ts=32.00&tt=12.00&cu=EUR) but it messes up with the other order data, such as the channel the order was generated from. 

Does anyone have any tips on how to avoid this and convert the local site currency in the currency used in Google Analytics?

Thanks!