If you look at the details for the ones posted on SLS, they will usually say if they allow SMs or not. Also, if you see SMs on the RSVP list then it's likely they allow SMs
The parties that YOU see on SLS will be based on your location, so it's not like I can easily see what parties are available to you unless we lived close to you.
To see parties, click on Hot Dates then click on Events for days you're free to attend one.