Yes, validator node registration includes an "allowExternalDelegation" flag. When this is set, only a single address may delegate new stake to the node: a special "owner address" specified by the validator node-runner.
The node-runner should set this owner address to one they control, such as an address created in the Radix Desktop Wallet. Once that address is set up, node-runners will be able to stake to their own node from this address and receive emissions as normal to this address, even with the allowExternalDelegation flag turned off. For security, it is strongly advised not to set this address to the node's own address.
The owner address can be seen as part of the validator ID info, and stake from this address can also be seen listed separately. If the validator node-runner has specified a validator fee, any fee emissions will also be credited to this account.
Note that turning off the allowExternalDelegation flag at a later time does not change any existing stake delegated to the node. This stake continues to gather emissions and contribute to the node's selection for the validator set for each epoch. This means that the flag may be used if the node-runner feels that their node has received more delegated stake than they are comfortable with or to encourage stakers to delegate to other validators with less stake to benefit network security.
Radix Tokens Jersey Limited will set this flag immediately to false for all of its nodes as part of its staking policies to ensure community staking goes only to community-run nodes.