Using a Different User Table

I use a custom login plugin called Simple WordPress Membership (https://wordpress.org/support/plugin/simple-intranet-directory) and I would like to use the Simple Intranet Directory — I like the functionality a lot.

I would like to pull the user data from the following table: wp_hlpa_swpm_members_tbl instead of the WP user table. Is there an add-on to make this change or can this change be easily made in the code?

https://wordpress.org/plugins/simple-intranet-directory/