As per Section 42(2) of Companies Act 2013 private placement can be made to maximum 50 persons or such higher number as may be prescribed in a financial year. However, this Section has not yet come into force. As per Proviso to Sec.67(3) of CA 1956 offer to 50 or more persons will be treated as public offer. It does not put restriction on number of times the offer can be made to 49 persons on private placement basis in a financial year. Unlisted Public Companies (Preferential Allotment) Rules 2003 are not applicable to non-convertible preference shares.
Hence as of now this should be possible under Companies Act 1956.