It is not recommended to split up your seed words[1]. Do not try to build your own scheme. If you want to store your keys geographically it is recommended to use multisig. You can also use a passphrase (13th/25th word) that can be stored separately from the 12/24 seed words[2].

[1] https://bitcoin.stackexchange.com/a/98423

[2] https://en.bitcoin.it/wiki/Seed_phrase#Two-factor_seed_phras...