As things stand after round five of South Africa's leading domestic competition, those four sides all occupy places within the top five of the 2008 Currie Cup standings.
Only the Blue Bulls look down on the Lions' opponents, topping the eight-team table with 18 points from a possible 25.
Two of those opponents came head-to-head last weekend, with reigning champions the Cheetahs recording an impressive 31-9 demolition of the Sharks at Vodacom Park in Bloemfontein.
Ian McGeechan's squad face the Cheetahs at the same stadium in their third game on tour on June 6, before taking on the Sharks in Durban just four days later.
There will be no let up for the Lions as they travel to Capetown to meet Western Province on June 13, exactly a week before the all-important First Test against the Springboks on June 20.
Although Western Province could only claim two bonus points from their most-recent fixture, the tourists' first opponents next year, namesakes the Golden Lions, gave note of their capabilities as they jumped into second spot in the table.
The Golden Lions secured a try-scoring bonus point inside 46 minutes and, although they had to withstand a strong second-half comeback from the Griquas, last year's beaten finalists now sit just two points behind the Blue Bulls.
Currie Cup results round five
Cheetahs 31-9 Sharks
Griquas 32-36 Golden Lions
Kavaliers 10-26 Blue Bulls
Valke 38-32 Western Province
Currie Cup standings after round five
Blue Bulls 18 points
Golden Lions 16
Western Province 12
Wildeklawer Griquas 9
Boland Cavaliers 7
Currie Cup fixtures round six
Friday, July 25
Cheetahs vs Valke
Saturday, July 26
Western Province vs Kavaliers
Sharks vs Lions