Using custom lists from other tables

I’d like to know if it’s possible to use a custom query so that we could either
— use the list of another plugin, Simple Membership SWPM or
— use perhaps the wp users list
– or import a list from either of these

But still be able to retain info from those who wish to change subscription info/status?

I’m happy to buy the premium version if it can give us this extra functionality.

We have subscribers to an online magazine and want to filter from their numbers to select, track and update this list PLUS those who have added their name for just the free newsletter in a single list.

Thanks for your help!
George