As Croatia is not part of EU yet. But they will soon this year. They exempt visa for anyone who holds Schengen visa in these types. http://www.mvep.hr/MVP.asp?pcpid=1615&dmid=92#pocdrz
* residence permits issued by one of the Schengen area members
* uniform visas (C) or
* long-stay visas (D) issued by one of the Schengen area members
However, upon arrival (as I have done this last year) you get a stamp from Croatia border that you're inside Croatia and when you enter Schengen country again you get another stamp from Schengen country border. This counts that you're out and in again (I held multiple entries). I guess it's safe to say that you need multiple entries visa. But you should check with the embassy in India.