In Do multiple GIS software tags equal multiple questions? the issue is raised as to how to respond to certain combinations of tags, in particular the presence of tags for multiple GIS software systems.
Is it possible to program the web site software to recognize certain combinations and pop-up a message to the OP?
In the cited case, the trigger would be the presence of two or more tags from a set comprising software systems and the message would be to either replace them all with gis-principle or select the tag for the software system of primary interest.