There are no restrictions on publishing a virtual tour on realtor.com. You only need to have virtual tours created in the Asteroom app and click the publish tours to listings on realtor.com.
To make your listing more attractive and interactive, you may order Asteroom imaging services.
The most important thing is the tour address should be exact identical with the listing address shown on realtor.com.
Notice: This feature is only available for users and listing addresses in the US.