Erm, definitely don't use these forums as your secondary research, they're not reliable! But I can understand you have an interesting idea, and you could use the ideas to research specific aspects about generational attitudes towards hindu-muslim relationships.
Also, if you can get people from these forums who told you the information and interview them/ get them together for a focus group IN PERSON, you could pass that off as primary research=D
As a Muslim, I have to say that it would be religiously forbidden to pursue such relationships because your religious beliefs are too different if you were to say raise kids at some point in the future I hope you don't mind my bluntness
But as your online internet buddy, I personally know other people who share the same views as you and have had similar experiences to you so if you you pull it off well, it could be quite interesting for you and educational hopefully.
I recommend you grab some scholarly articles for secondary reserach (ask your school librarian/ public library they might be able to help if you tell them your topic and use your library card to access EBSCO etc online for actually reliable articles. Getting a NSW State Library Card also gives you good access to online reliable databases for secondary information
). Also, maybe for enhanced macroworld understanding you could get an expert interview with a Muslim and Hindu religious leader or something in relation to marriage/relationships for greater macroworld understanding.
I reckon something interesting to me at least would be applying content analysis to some Indian films e.g. Veer Zahra and examine how they encourage macroworld Hindu/Muslim relationships in contrast to your microworld experiences (and I believe I can confidently say many of your peers). You could seek to use the cross cultural factors of religion and generation to explore a potential shift in attitudes between generations maybe, specific to Australia or something in examining the effect of specific media/macroworld influences on microworld attitudes of Hindu and Muslim youth relationships.
You could explore how multiculturalism is accepted to different extents, such as in regards to marital partners vs. peers. For example you could use a survey first (when you start primary research) to see whether the attitudes towards Hindu-Muslim relationships from a love perspective extend towards other types of relationships as well such as acceptable being friends and work colleagues or something and to what extent (like order 1 - 5 what would be the most to least acceptable relationships between hindu and muslim people against x criteria). But for something like that you'd have to ensure complete anonymity to try and make sure everyone answers honestly and to not offend your participants.
Make sure if you base it on your personal experience you don't make it sound too much like your life story and be objective and stuff
Hopefully that's a useful starting point - good luck