Running the report defaulting to top most member in TM1 security

[twister]

Hello Cognos Gurus,
Need your help.
I would like to run the report (by default) pointing to the top most element the user has access to. The report points to TM1 security.

Say for example, there is an entity dimension which has region and countries as levels and
a) If the user has access to Asia region, then the report needs to run automatically for Asia.
b) if the user has access to only country member (say for example Germany without any regional level access), the report needs to run automatically for Germany.
c) If the user has access to multiple members (say for example multiple countries) at the same level, pick one by random and run the report.

How do I do this?