(5) Any bank, trust company, mutual savings bank, pension fund, mutual savings fund society, mutual banking association, insurance company or any other type of organization defined in this section and investing funds in Mississippi may sue or be sued within this state in relation to such mortgages or deeds of trust on real properties, securities or debts and service of process may be performed by service upon any custodian or agent appointed within the state. If no such custodian or agent has been appointed, the Secretary of State shall be and he is hereby appointed and shall remain as the duly authorized agent of such organization upon whom such service of process may be had. In cases where such organization is sued, the venue of such action shall be in the county of the residence of the plaintiffs, or any of them, except where land is involved, in which case, venue shall be in the county in which the land, or any part of it, is located. The Secretary of State, upon the receipt of process by him on such organization, shall forthwith forward notice of the same by registered mail with return receipt requested to the post office address of such nonresident corporation, mutual savings bank or association and shall make a notation of said fact upon his process record to such effect.