After checking the command reference guide for mminfo usage, there does not appear to be an option you can pass to -r to extract information regarding the "type" of saveset which is unfortunate.

The only alternative I can think of is to use mminfo with the -N option.
For example:
If you know the type of saveset you're looking for always has the same name (Lotus notes for example has "NOTES:").
Then one could do something like this: mminfo -avot -N NOTES:
This will return all the Lotus Notes savesets from the mediadb.

Similarly, Isilon NDMP backups usually contain a leading /ifs/.. in it's name.
So one could use mminfo -avot -N /ifs to return all Isilon NDMP backups and so on...

nsrinfo has a nice option -n to query the namespace, this looks more along the lines of what you need...

–n namespace - Indicates the file index name space to query. By default the backup name space is used. The other recognized values are: migrated, archive, nsr (for internal use), bbb (for Block based backup data), db2 (for DB/2 data), informix (for INFORMIX data), iq (for SAP IQ data), msexch (for Exchange data), mssql (for SQL Server data), mysql (for MySQL data), notes (for Lotus Notes data), oracle (for Oracle data), saphana (for SAP HANA data), sybase (for Sybase data), and all. The name space field is case sensitive

This mminfo limitation looks suitable for an RFE.

Thanks I will try this out. I appreciate the help.