Microsoft Skype for Business Server 2015
Hello LH, The issue is understood now. Thanks for clarifying, the most typical use case seen when deploying director services is to also deploy FE services. So for the purpose of hiding questions unless they are needed the director services section was made dependent on FE services being set to yes as you observed. It appears however that you have a unique edge case where you would like those two sets of services managed by different iApps on different LTM's. We will take this under advisement and update the iApp accordingly.
As it sits for you now my suggestion is to simply fill in the FE services with a placeholder VS ip and pool member ip. I know that is not ideal but that will allow you to use the iApp without modifying it and making it unsupported.