Should I use panel causality Model?

[shahadath2005]

I want to test causality between Stock market index return and Mutual funds Return (22 mutual funds).

I am interested in total effect of mutual fund industry rather each of the mutual funds' impact on stock market.

Should I use panel causality model or not.

if yes, then should i use two step E-G causality test, as many researchers indicate 2-step method is not flawless.