Multiple VLAN's can be allowed in the access point by making the ethernet port as Trunk.
Here are the few commands to make the Access Point's port to Trunk.
Login to AP cli and provide the commands below:
rkscli: set interface type vlan-trunk untag 1
rkscli: set ipaddr wan vlan
- is the name of the Ethernet interface you are using to plug the AP into the switch, if the POE port is used it is "eth2" and so on(I used 7363 here).
Note: Enusure that you have DHCP server for each VLAN so that clisnts will get the ip addresses according to the VLAN setting.
Now, connect this AP to a switch port which is configured as Trunk that allows multiple VLAN's.
Now, go to Configuration > 2.4G or 5GHz and create the SSID and Tag the VLAN number. By doing this, clients connecting to this SSID will get ip address from that particular VLAN.
I hope this helps!