Ideas to connect external database table to wordpress posts as custom field source

I have a custom database table within wordpress database.. I filled this database with data and wordpress posts table with matching ids

an example would be...

wp-posts table has

    id - title
    1  - record1 title
    2  - record2 title

custom table has

    id - title          - data1 - data2 - data3
    1  - record1 title  - 20g   - good  - 200USD
    2  - record2 title  - 30g   - fine  - 100USD

I can reach data with custom php coding and sql queries when i open a post

lets say if i go www.demo.com?p=2 I can display,

Title - record2 **with the_title()**
details - 30g - good - 200USD **with php+mysql**

what i want to do is connect them with custom fileds so that i will be able to edit them in backend and display them more easily without writing custom php+mysql coding..

I checked ACF and several custom field plugins.. they seem to create their own tables or store data in postmeta

This wont work with me since i am using this external table with other php coding other than wp.

I looked at some frameworks also.. Couldnt find the best answer yet..

since i have same id's for wordpress posts and custom tables records is there an easy way to do it without writing code.. Or less coding..

Thanx