Merging option set fields together

Repost:

Hello all,

I wanna create a custom topic field in Leads which combines - Company name + country + business type + subject. Out of these, the country and business type fields are custom option sets that I created. When I try to concatenate these fields, it doesn't allow me to select those Option sets/Picklists.

I read in a blog that it is possible to concatenate the option sets in CRM online. Also, I tried to search a tool for merging the fields in XRMToolBox, however couldn't find one.

Thanks in advance for your suggetions.