There is no dual specialization in any of the b-schools. In most of the b-schools you get to do major specialization in one of the stream along with minor specialization in other stream.

In IIMs it is a little different as you are given a General Management degree and there is no major or minor specialization in any stream.

In almost all the b-schools you are being taught subjects from all the streams in first year then at the end of the first year you are given an option to select in which stream you want to do major and minor specialization. In case of IIMs again a little different you are given opportunity to select all the subjects you want to study in second year with min and max credits barrier irrespective of the streams depending on all your interest.

So this approach gives you enough time to figure out which stream is more comfortable for you and in which you want to pursue your career.

As you are interested in HR management then you can take it as your Major specialization. With HR for minor specialization marketing is one of the best option but finance and operations are also good. It will be better that you choose minor course in the end of first year. In case of IIMs you can select all the courses of HR and few other courses of other streams depending on all your interest.

Instead of worrying about stream, right now you should focus more on MBA exams because that is the first step you need to clear.

All the best!!

Marketing will be better