If you have multiple logins for a particular domain, LastPass fills in the closest URL match by default but will show all sites from that domain in its matching list:
This behavior can be changed to only show sites that match particular hosts/paths by managing your URL Rules. To manage your URL Rules, launch your Account Settings. In the menu that opens, select the last ‘URL Rules’ tab:
If a URL Rule is created with exact host matching, then you will only be presented with logins that match the exact host for that domain. For example, if you create a rule with domain=facebook.com and specify exact host matching=yes, then when visiting www.facebook.com, you will only see sites saved from www.facebook.com, but will not see sites saved from login.facebook.com.
If you specify a URL Rule with a path, then only sites that match this path will be shown. For example, LastPass created a default URL Rule for google apps with path=/a/. This causes you to only see the appropriate logins when you visit google.com/a/aaa versus google.com/a/bbb.
You can delete a URL Rule at any time by clicking the grey ‘x’ next to the domain entry in the URL Rules tab.
By default, LastPass stores a URL Rule for some sites for your convenience. Sites are added and updated as we discover them.