im not quite sure wheter hex is supported in maskfile or not. but i would try building up a maskfile for that, starting with (INFO in maskfiles, custom charsets (up to 4) are divided by , ) and then add ?1?2 multiple times, each line = a whole mask (manual bf)
c3,a4a5b6,?1?2
?d
c3,a4a5b6,?1?2?d
c3,a4a5b6,?1?2?1?2
?d?d
c3,a4a5b6,?1?2?1?2?d
c3,a4a5b6,?1?2?1?2?1?2
?d?d?d
i hope you get the point
EDIT:
quick test with
hashcat -a 3 --stdout --hex-charset maskfile.txt seems to work like expected (stripped the lines with single char/digits)
å1
ö2
ä1
å2
ö3
ä2
å3
ö4
ä3
å4
ö5
ä4
å5
ö6
ä6
å6
and so on
c3,a4a5b6,?1?2
?d
c3,a4a5b6,?1?2?d
c3,a4a5b6,?1?2?1?2
?d?d
c3,a4a5b6,?1?2?1?2?d
c3,a4a5b6,?1?2?1?2?1?2
?d?d?d
i hope you get the point
EDIT:
quick test with
hashcat -a 3 --stdout --hex-charset maskfile.txt seems to work like expected (stripped the lines with single char/digits)
å1
ö2
ä1
å2
ö3
ä2
å3
ö4
ä3
å4
ö5
ä4
å5
ö6
ä6
å6
and so on