K2 Adapter of JoomGrabber support K2 custom fields, so you will be able to fill your k2 custom fields with grabbed data easily.
1 - Link Field Type
We do suggest to use combine processor to combine text (label of link) and value (link) with separator || , example: My link||{[oe] link}
{[oe] link} is the link from engine output like RSS engine.
Note: make sure to click on toggle button to be able to add separator
2 - Multiple Select Field Type
Also same approach as Link field type, you need to use combine processor to combine your selects using separator | , example: select1|select2|{[oe] text}
Note: make sure to click on toggle button to be able to add separator
3 - Other Field Types (Text, Text Area, Select)
Doesn't need any separator for combining values, just wire your processor or engine output to k2 adapter field input