[Divingduck]

Not sure if I get your request correct. a example could help for each variant

When you need more differentiation than less, equal, greater then the function switch() is maybe more suitable for your task. Something like:

program: 
tmp0 = template('No Crossovers/{author}/{title} ({#story_id})');
tmp1 = template('{#fandom_main:sublist(0,2,\,)}{#fandom_secondary:sublist(0,2,\,)}/{author}/{title} ({#story_id})');
tmp2 = template('Crossovers/{#fandom_main:sublist(0,2,\,)}{#fandom_secondary:sublist(0,2,\,)}/{author}/{title} ({#story_id})');
tmp3 = template('Multiple Crossovers/{author}/{title} ({#story_id})');

## old version check if count is lt, eq,gr
#	cmp(
#		count(
#			field('#fandom_main'), 
#			','), 
#		3, 
#		tmp1, 
#		tmp2, 
#		tmp2);

## new version as "case of count =x"
switch(
		count(field('#fandom_main'), ','),
				0, tmp0,
				1, tmp1,
				2, tmp2,
				3, tmp3,
				tmp3);

# in first position of a line means it is a comment, you can delete them if you want. The mechanism works like "if count = 0 use template 0, if count = 1 use template 1 up to count =3 and if count different to 0,1,2,3 use template 3 (or what ever else you want to do


Regarding the '-', you can use as well |-|, || or |-|- for a prefix and/or suffix