You could use a relay.tools relay which supports hashtags and has a built-in Web of Access (WOA) feature to eliminate spam. Spin one of those up, add it to your relay list and it should do what you want.

nostr:npub1fvmadl0mch39c3hlr9jaewh7uwyul2mlf2hsmkafhgcs3dra6dzqg6szfu

nostr:npub10npj3gydmv40m70ehemmal6vsdyfl7tewgvz043g54p0x23y0s8qzztl5h