Create a multi choice field from a relationship

OMG. I am dying. This is EXACTLY what I wanted

:)

What if I don't want all records from Table B but only those, as text-multiple choice list, which the field Status=In progress?

If you just want to select 1 choice on a drop down list then you can make a relationship  and use a report on he form to limit the choices to just Status = In progress.  But that technique will not work for a multi select field type when you are choosing multiple selections n that one field.,

hum..ok

I need a multiple-choice field (Activity category) where choices are depending of the status of the program selected. 
Can I set up a formula into the Text-Multiple Choice instead of a "hard" list?

Thanks

See my post above

If you just want to select 1 choice on a drop down list then you can make a relationship  and use a report on the form to limit the choices to just Status = In progress.