SQLite database partitioning

I want to create sqlite partition structure, I created 3 databases, I attached those 3 databases to another database which will be parent with

ATTACH DATABASE '1.db' as 1
ATTACH DATABASE '2.db' as 2
ATTACH DATABASE '3.db' as 3

after i .quit the parent database the database attachments detach, How can I keep them attached even if I quit the database? Thanks.