Question about adding data in Access

Im sure the answer to my problem is really simple, but I can’t see it:

I want to add a table of data(brought in fr Excel, currently an independant table in Access) to my db, but I need it to be divided to go into three tables that already exist in a many to many relationship. The fields in the new table all match those in the pre existing setup, where the primary keys are autonumber fields.

I know I can use an append query three times, but this method won’t pick up and carry across the autonumbers into the link table. I could also copy and paste but this is impractical as Ill need to repeat the process many times later.

Is there a simple way of dividing up new data (already in a table) and slotting it into a simple three-table many to many setup?

Thanks