[Plugin: Simple Fields] How to add two default post connectors

Simple fields is great, thank you.

What I want to achieve is the following:
1. Custom post types of my creation. Done.
2. Multiple groups of Simple Fields. Done.
3. Freedom to choose more than one group of simple fields for a single post type. Not possible?

The problem is that Simple Fields has a drop-down box that only allows one group of fields to be the default post connector for a post type. Therein lies the limitation.

What would be great is if the drop-down menu is replaced with a check-box list.

In this way, I can create different post types and simply tick off the field groups I want to be default for that post type. Custom fields could then be shared across different post types, instead of having to be repeated.

As it stands, I have to create a different post type for every group of fields that I create, which is not ideal.

I understand that I can simply create all the fields I want for a single post type, but I want to group the custom fields with different headings for different purposes.

Is there a way to achieve what I need?

Thank you.