Can I spend utxos from various bip32 subwallets in only one transaction? I want to redeem bitcoin received into several bip32 subwallets in only one transaction. Is that possible?

I've tried using pycoin's ku utility to generate a tpub and a wif from a tprv. I'm using the tpub to generate the subwallets and the wif to sign the transaction, but pycoin says the signing fails.

Is that conceptually wrong, or am I just handling the keys in the wrong way?
a Bitcoin transaction can have between 1 and (realistically) several hundred inputs, each of which can redeem completely unrelated UTXOs. Whether or not the keys for those UTXOs are related through BIP32 or some other scheme is not relevant, and even not observable by the network (it is not possible to correlate different BIP32 keys unless you know their master key).