i have 3 tables, one for one purpose and another for eitirely different purpose. Side-Note: I have relationships between the single tables and the joint table.
And those relationships are? And what are those purposes?
Knowning those details would help us to better help you.
You might consider changing the sequence so that you create the record in the "big comparison table" first and then, from the context of that new record, create the needed record in the related child table. But a script can change layouts to the combined table, create a new record, copy the ID of the new record to a variable and then return to the layout and record from which it started to copy the value from the variable into the correct match field to establish a link between the two newly created records. But, depending on the relationship details, it may also be possible simply to select new record to create a new record and when you enter data into the fields on the layout, the needed related records is automatically created without the need for a script.
The purposes are one for a list of unsubscribers the other is the current list. the "comparison table" is a combination of the data of both to search for duplicates etc.
And the relationships are between the current table and comparison table are all the fields with Delete and Create options ticked, as is the same with unsubscribers table with the comparison table. there is no relationship between the current and the unsubscriber tables.
does this makes things easier?
The purposes are one for a list of unsubscribers the other is the current list.
I would recommend that both records be entered into the same table rather than one. This both simplifies your relationship graph and allows records to move to and from "Unsubscribers" just by changing the value in a status field in the table. It also allows you to much more easily produce reports that list records or summary data from both subscribers and unsubscribers.
And there will still be many ways that you can automatically pull up lists or found sets of recors that are strictly subscribers or unsubscribers.