I always don’t suggest choosing too many search engine when checking the keyword rankings, as it will take longer to complete the querying process and may cause blocking by the search engines. So I often suggest choose which matters most to your business.
However, if you’ve already set a lot of search engines for the profile i.e. the website, and you want check the keyword rankings only for Google, here is the solution. Of course you can use the same way to check Bing or Yahoo only.