WLC 5508 Interface Group with one interface for static IP addresses

[NotJane]

We have an 5508 WLC with an Interface Group containing 3 interfaces with an DHCP pool "behind" each one. Now we have a need for an interface with static IPs only, and have added this to the Interface Group since the SSID needs to be the same. How do I go about not having VLAN Select send DHCP clients to this fourth Interface without a DHCP pool? 

With the command show 'interface group detailed <interface group name> '  I can see the failures and Dirtytime for this fourth Interface, seems to go to about 1800 secs and then the timer goes to zero and 3 new fails (Failure-Detect Mode = Aggressive) have to happen before WLC marks it as dirty. Can I change the timer for this interface to a really large number to not have to have some client failing it´s DHCP Discovery every 30 minutes.

I´m guessing DHCP Proxy Mode doesn´t matter in this case, having it disabled will only make the WLC pass the broadcast to the VLAN and even if that SVI is without IP Helpers it will still have DHCP clients sent to it through VLAN Select..

[Scott Fella]

I don't think you can have a mismatch in an interface group like what you want.  You are almost better to use radius and send an attribute to have radius send the vlan id the device should be placed on.  Interface group will round robin which interface a device will be placed depending on the algorithm used.

Maybe what is better is a new SSID that those devices connect to and it is just mapped to that one vlan.  That is the simplest solution.