What does 'g_' stand for in the g_siteowner field? Many developers use that to identify a field with global storage. Is this a global field?
1) is a case of setting up a conditional value list. Option 1 of the first link in the following set of links describes one simple way to set up such a list by using a calculation field that is empty unless the record is for a siteowner as the source of values for the value list.
2) We always have to be careful in this situation. What exactly do you want to find when you select an organization from this value list? Do you want to find all Developments records that have at least one related Organization record for this organization? Or do you want to pull up that organization record? Or do you have something else in mind?
My links on conditional value lists:
There's a lot of overlap between the first two links so you can read one and skim the other. The demo file gives you several examples of different conditional value lists so you can examine them to see how they are set up. If you are using FileMaker 12 or later, you can open this demo file from your File menu to get a converted copy of the demo file that you can examine in your version of FileMaker.
The next to last link discusses how to set up a chain of conditional value lists where the value selected in each conditional value list controls the values listed in the next value list and the very last link is a fairly new addition that describes how to use ExecuteSQL to produce conditional value lists that aren't easily possible with the other methods described here.
Forum Tutorial: Custom Value List?
Knowledgebase article: http://help.filemaker.com/app/answers/detail/a_id/5833/kw/conditional%20value%20list
Hierarchical Conditional Value lists: Conditional Value List Question
Using ExecuteSQL to produce a conditional value list: Using ExecuteSQL to Produce a Conditional Value List
Feel free to post follow up questions here if those links aren't enough to get your value lists working correctly.