Dual ground net?

[1wildthing]

Hi guys, I'm working on the attached schematic at the moment.
As you can see the relay's grounds have been designed with a Black arrow symbol. Differently, other ground symbols are white arrows. As it's the first time I see this kind of thing I'm a bit confused.
Does it means that I have to design a separate ground net for those Black grounds? May be I have to send them directly to the star ground?
Or may be they can be added to the main ground net?

 

[Voyager10]

'Black' ground and 'white' ground are connected together at a single point, in the power supply section in the bottom right.

I expect it's to stop current spikes from the relays being coupled into the audio path. It's a common arrangement - many mixed-signal circuits have a digital ground separated from analog ground, joined together at a single point. (See for example https://www.analog.com/en/analog-dialogue/articles/staying-well-grounded.html)

 

[Newmarket]

Keep separate to keep relay coil current out of audio signal 0V. Route back to PSU or can be an isolated supply.