Is this possible?

Is this possible?

Hello all - I know this is probably an obvious question but I'm kinda tired of reading all the help sections and messing around with the program without finding a conclusive answer. Here is what I would like to do:

I made a spreadsheet with only a few columns (I wanted one to be a drop down.... But I found that Zoho does not support them... lame... Anyway, what I need is about 30-40 computers at once to be able to access the spreadsheet and be able to change the data in two of the columns as they accomplish their tasks. And for those changes to be reflected on everyones view of the document. 

I'm pretty sure that's possible, but I would like the document to be password protected - It can be one username/password for everyone to use - but it can't be freely available on the net. I am sure that's possible, but I have no desire to spend 700$ for it. 

What do you all think?