How about doing this kind of over-simplified model...forget about the distinction between "judging" and "perceiving". See functions only as extroverted (those that interact with the external world) and introverted (those that are used to analyze or understand the information).

Then we have a simple model:

1. Get information in with some extroverted function
2. Understand/analyze the information with some introverted function
3. Affect the world with some extroverted function

Most likely you will use your ego-block functions but you could also choose to use some other functions.

E.g. in the case of ENFj (when relying only on ego-block):
1. Get information in with Fe
2. Understand the information with Ni
3. Affect the world with Fe

Same process happens with INFp but with the difference that ENFj spends more time taking information in and causing effects where INFp spends more time understanding the information. Subtypes have same kind of effect.

Now technically you could switch functions there "on the fly".

So ENFj could e.g.
1. Get information in with Fe
2. Understand information with Ni (or perhaps choose to use Ti)
3. Affect world with Se (instead of Fe)
however the effect would likely be less optimal than when using the strong Fe as effector.

There might exist some additional rules which dictate how you can "chain" the functions and that you can't do it freely. I once had a more complex model in mind but it made my head hurt. Currently I stick with this one, lol. It is simple enough to be evaluated or applied in practice. It might be complete crap too, lol. At least it should be extended somehow I guess.

Really I don't know if this is Ti or not. At least I gave it a shot, lol.