This is possible.
One option might be, to use wildcards or regular expressions in the maintenance plan,
but that would require some idea of the name of the future database. If that doesn't work, either edit the maintenance plan directly or use the TSQL LiteSpeed API to create your own custom script that back up via grabbing all the databases listed in a custom table in msdb and they could directly update the table when needed from TSQL.
If you prefer to use just a t-sql script that calls databases by some or of variable or temporary table,
you could write your own script using xp_backup_database.(note: We don't support custom scripts)
I’ve attached a basic script that may help get an overall idea
The parameters for xp_backup_database are in the Help file, Help|Help contents xp_backup_database
