It is not necessary to invest in multiple liquid funds if you want to invest for your client through Systematic Transfer Plan (STP) in equity funds of different fund houses.
Invest in just one good liquid fund. Subsequently, set up a Systematic Withdrawal Plan (SWP) to your client’s bank account and an SIP in an equity fund. You will have to give the instructions once and then the money will come to your bank account automatically every month for the SIP.
So, you may consider investing only in one liquid fund and set up an SWP along with SIP, instead of going through the STP route. STP is nothing but a combination of SWP and SIP.