No, it is not possible to create multiple portal accesses at once. But there are some things you could do to make this task easier.
To grant portal access, you must create it individually for each user. Unfortunately, it is not possible to select multiple portal users and give them access all at once. However, there is a way to make this process a little easier.
To grant portal access, you need to create it for each user individually or for the desired entities (learn how to do it here). At this stage, avoid selecting specific checkboxes to grant someone the right to access specific information. Simply leave them empty for now.
After granting access to all the required users or selecting the desired entities, you will have the ability to edit the rights in bulk.
Click on the guided demo below to learn more