Hi,
Yes, it is possible.
You could deploy a hybrid environment, which will include the features introduced in the official document below
Exchange Server hybrid deployments
Then you can choose the users you want to move to cloud, and other users still locate on-premise
Detailed information here: Move mailboxes between on-premises and Exchange Online organizations in hybrid deployments
For the guide to help you deploy your hybrid environment, using this: Microsoft 365 and Office 365 mail migration advisor (login your Microsoft 365 or Office 365 account with Global administrator permissions)
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