Windows 7: How do I limit Windows Homegroup sharing to specific people?

Hi. Basically, I've set up a homegroup specifically to stream Bluray movies to my mum's computer, but my sister wants in on the action and connects to my computer to watch my collection of movies even when I tell her not to. I wouldn't mind but this consumes quite alot of bandwidth. Are there any ways to limit my sharing to just my mum? Or to kick and/or ban my sister's computer from my homegroup?

as it is almost xmas you could do the brotherly love thing and ask her to limit how she views your movies,
you could for instance ask her to limit streaming by copying the movie from the homegroup to her hardrive, then she can delete it once viewed.ask her to copy one or two a day as she probably doesnt watch more than that.
explain that streaming eats up the bandwidth which is no good to anyone else who is sharing it, failing that get your mum and yourself to leave the homegroup set up a new one with a new password, and dont tell her the password.
or if its possible change the password daily letting your mum have it and your sister has to do your chores before you give her the password.
but remember sisters can be evil when it comes to payback.
and it is nearly xmas , remember sharing is caring!

yes! passwords! genius! :P i would love to share but she's not the kind i'd want to waste my time explaining the meaning of bandwidth to. thanks for the help

You can simply remove the sisters machine from the Homegroup or you can add that sisters machine as a standard user account on your own machine. This will make her PC show up on the shared with list and you can set the permissions for that machine as desired.