What is the legal test for joining a third party?

In Ryan v. Dew Enterprises Ltd., 2014 NLCA 11, Green, J. identified the following guiding principle for joining third parties (at paragraph 58): 58. ... As noted, this section is the statutory authorization for third party procedure. It contemplates a person being joined as a third party whenever the defendant is making a claim "related to or connected with the original subject matter of the proceeding". That language extends beyond contribution or indemnity claims, inasmuch as it does not require the defendant to claim to pass on liability for the plaintiff's claim to the third party. All that would appear to be required is to show that the defendant's cause of action against the third party arises out of the same general factual and/or legal matrix of the extant issues between the plaintiff and defendant.