If the only meeting that Montreal hosts is in the spring, which one of the following could be true?

When initially setting this game up, I wrote the first two rules as Hf-->Mf Ms-->Hs and Vs-->Ts Tf-->Vf For the contrapositives of the two rules, I was under the assumption that M not being in fall meant M was in spring which invokes H being in spring. I did the same for the second rule. I have used this strategy on other group games involving two distinct groups and haven't had an issue. I'm confused as to what makes this game different and how to identify when this strategy can be used or not used?