Thanks for the response guys.
To clarify, the LOC will be used to capitilise interest.  From reading through the forums, the general trend is that investors set up different sub accounts for different IPs.  However, these sub accounts incurs extra cost to maintain.  For example, can ppl have one big LOC to capitilise say 3 IPs and not separate them? Will this cause many problems at tax time?  But remember that it will only be use for investment and no personal borrowing.