Nested IF with multiple criteria

I need to be able to pick sports from a list under each term... there are four terms. However, certain sports cannot be picked if another particular sport already exits, e.g. swimming cannot be picked if rowing has already been picked for term 1, etc.

Requirements:

1 "Rowing" is specific to term 1, "Swimming" to term 2, "Tennis" to term 3 and "Squash" to term 4 (none can be picked if another has been picked).

2 But "goals" is a sport that can be picked regardless but only once over the four terms.

3 The error is to to displayed under the offsite column. I have already sorted the IF statement rules for onsite and it works. e.g the first entry should be an error. I hope this is clear.

How would I go about doing this? Would I need a giant IF?

I have attached a sample.