How to make TortoiseHg pull certain branch only?
This can be done from the Synchronize area of the Workbench. Click the Synchronize entry on the View menu or the Synchronize toolbar icon (2 green arrows appearing to form a circle). In the bottom right pane, click Options. Enter the branch name you'd like to pull in the Branch: edit box. Finish the pull as usual.
hg pull -r <branch name>
For more info: https://stackoverflow.com/questions/5796908/mercurial-how-can-i-import-only-some-changesets-from-a-repository/5798221#5798221