Hi Devlend,
Normally something like this can be accomplished using Filtered Lookups: https://success.clarizen.com/hc/en-us/articles/360025841193-Filtered-Lookups-for-Custom-Action-Forms
However, IsMemeberOfGroup() function can't be used in this context. It also can't be used in formula fields that could be used for such filtering later on.
The only option I see is to create a custom toggle field (e.g. C_isEVPJobTitleHolder) and populate it using other means (workflow rule, scheduled workflow rule). Then this field could be used in Filtered Lookups like so:
I hope this helps.
Roland