I've set my Synology NAS to update Dynu hostnames following this guide:

https://www.dynu.com/DynamicDNS/IPUpdateClient/SynologyNAS

It only works with one hostname though - but I have 3. I've created a group and placed the 3 hostnames in to it. On the NAS I set the Group name instead, but this doesn't work at all. Is there anyway round this?

Could the following be changed to set 'Group' instead of hostname:

Service Provider: Dynu.com
Query URL: https://api.dynu.com/nic/update?hostname=__HOSTNAME__&username=__USERNAME__&myip=__MYIP__&password=__PASSWORD__

Thanks

All I did was create two custom ddns providers.

First one contained:
https://api.dynu.com/nic/update?hostname=__HOSTNAME__&username=__USERNAME__&myip=__MYIP__&password=__PASSWORD__

Second one contained:
https://api.dynu.com/nic/update?hostname=nextdomain.com&username=__USERNAME__&myip=__MYIP__&password=__PASSWORD__

The first one hostname was blank because it was the default domain, but I had to enter a domain for the second one.