Booking RT, abandoning the return and flying only OB on Qataar Airways?

[theglobalinvestor]

Can anyone advise on the following scenario?

Booking RT one way Qatar Business and return Economy because almost $1k cheaper than one-way in Business.

1. RT A-DOH-B OB in BUSINESS on 22/5 and IB in ECONOMY on 20/6 or any date in the future to be abandoned/cancelled.
2. RT B-DOH-C OB in BUSINESS on 20/6 and IB in ECONOMY on any date in the future which may or may not be abandoned/changed/cancelled.

Can I have an open/incomplete RT journey while embarking on another RT journey?

Multi-city routing A-DOH-B-DOH-C is not available as required.

Please advise!