Just look at the master rule options:
You can define a rule based on the browser type:
- Microsoft Internet Explorer
- Nokia WAP
and browser version like: MSIE
Assign a destop for the specified browser with framework and theme. So: yes, it's possible.
Define rule based on browser type by specifying the corresponding desktop to it.
MastHead Change & Portal Desktop: MastHead Change & Portal Desktop
Portal Display Rules (Rule Collections): http://help.sap.com/saphelp_nw70ehp1/helpdata/en/48/1d5cfe71364269e10000000a421937/frameset.htm
Hope this helps you.