Diff. between searchable/adv. searchable in field settings

Anyone know what the difference is between searchable and advanced searchable in the field settings?

I'm asking because I have some fields that have specific access control settings for fields, something like this:

Type Article has two fields A and B where group X can see field A while group Y can see field B.

When I make both fields searchable, they will both appear in the search index, which means that group Y can read field A or group X can read field B on the search page.

So I have to make the fields NOT searchable, which sucks. I have looked at the search plugin code, and it does not seem to take field access rules into consideration.

I guess my real question is: Can I make field A searchable for group X only, and field B searchable for group Y only — in any way?

no sorry i thnik it's not possible ...