If one your HSBC account (any countries) meet the premier requirement, you just need to inform the local RM to make the account as your premier home country. When you link your global account, HSBC system in any of the country can see your premier status. For example, HSBC Singapore can view globally the account you have and which country meets the premier status.
HSBC Singapore is my premier home country but I have HSBC HK, HSBC AU, HSBC UAE, HSBC UK, HSBC Jersey, HSBC USA. I also meet HSBC Australia premier requirement but I did not make Australia as my premier home country (you can only select one premier home country). The rest of the account, you don't have to meet the TRB.
When you move the fund from MY to SG and meet HSBC SG premier, you need to inform your RM to set HSBC SG as your premier home country. They will update the HSBC global directory. This is how the information being send to all your HSBC accounts globally.
I have once walk into HSBC Australia branch and they show me their system which they can see where I have HSBC account and which countries meet the TRB and which countries is my premier home country. This is how the international banking services who help premier customer to open account overseas. They can see if you are a premier customer.