When configuring a Virtual Access Point Group, this supports up to 8 Virtual Access Points.
However, when the group is assigned to both Radios (Radio 0 and Radio 1) of a SonicPoint NDR, the maximum number will be 4 VAP as the SonicPoint NDR supports maximum 8 Virtual Access Points (so 4 VAPs per radio or 8 VAPs if using only one radio).
Regarding SonicPoints ACe/ACi/N2 the limit is 16 VAPs so you can use up to 8 VAPs per radio.
SonicPoint NDR supports up to 8 VAPs in total among Radio 0 and Radio 1.
SonicPoint ACe/ACi/N2 support up 10 16 VAPs in total among Radio 0 and Radio 1.
As a workaround, if more than 4 VAPs are needed on SonicPoint NDR, we suggest to disable one of the radio.