PVLANing both switches in RB1100 to one uplink port

Have RB1100 with 10 ports and two internal switches.

I understand PVLAN but it wants an uplink port on the same switch as the isolated ports.

How can I transparently isolate all ports 2-10 with one uplink port 1 or do I have to have two uplink ports one for each internal switch?

Or can’t I?

Thanks in advance, Homer