Hi , Yes you can do that
1st create : Tag - go to settings :Devices & Users > Tags> Create Tag
2nd link that TAG to your smart group: Edit your smart group & add tag in the Criteria. if that option is not available then create a new smart group with that Tag.
3rd Assign new smart group to all your apps.
4th Import devices using Batch import function. Go to Devices >lifecycle>Enrollment Status >Add> Batch Import> Download the template for User and/or Device .
then fill the details like serial number , IMEI , USER & in Tag column : mention the Tag that you have created.
Upload the batch file & the device will automatically get assigned to your smart group.
further apps will get pushed.