Post your news and requests for information in the forums, which has topics for finding whanau (family), whanau events (tangihanga, funerals, reunions, anniversaries etc), general korero as well as events.
There is also a calendar which you can add your events to and a link section where you can add your Maori sites.
I have just had a quick look around and here are some options for you to try.
If you make sure you are at the Whakapapa Club (your login at maori.org.nz works at the whakapapa club in case you signed up there) and put WAIHI in the Search the records at the top of the page you will get a few results.
Under the search results heading you will find 7 Lists found matching search criteria so click that link (as the others are not relavant for you) and you can look aorund in there - I am not sure which ones could be your whanau.
Go to the Whakapapa Club Research Archives, put Waihi in the search box and there are more results you can look at.
Go to the Whakapapa Search on Google and FamilySearch page and put Huatahi in the first name box and Waihi in the Last name box and click on Create Searches. Once that page loads, click on the Google Search button next to where there is code. You will find results there but some are part of the myheritage site which expects you to sign up to it, but you can see some names and then search for those.
From the Whakapapa Search Page where you created searches, click on the link under FamilySearch Site and you will find no results on the page that pops up, so on that page remove the first name and click update and have a look around those records.
Note, the FS site can have typos and other variations of names (make sure you have looked at Maori Naming Conventions if you are not sure how they work) but it is a good place to start.
Nau te raurau,
Naku te raurau,
Ka ora ai nga tangata!
Together we will get there!