Marantz 5006 multiple connections

I have a Ipad
I have a Iphone 4s

Both latest ios, roomie 1,6

I cannot use roomie on more than one ios unit,
If I use both my Ipad and Iphone the live feedback Marantz ( volume) drops out.

Should it be like this ?

Yes, that’s normal. Denon (Marantz is a rebrand of Denon) only supports 1 connection at a time. Using an IP2SL/WF2SL (for models with serial support) is generally the best way around that as discussed at the FAQ:

The alternate control mechanism mentioned in the FAQ is unlikely to work with that Marantz model although it is possible.

this works on a marantz NR1603 over port 80. Any chance you guys are going to add this “IP” control method to the setup of the marantz? Right now I have it configured as a denon, not the end of the world but it would be nice to add this control.